commit 06226be0a8a79e31181ad5ad592865d675b9eb1e
Author: upstream <upstream@localhost>
Date:   Thu Oct 15 00:35:14 2026 +0200

    Upstream NaturalIntelligence/fast-xml-parser state of the touched files before 606d90c9d9

diff --git a/lib/fxp.d.cts b/lib/fxp.d.cts
new file mode 100644
index 0000000..eabd37d
--- /dev/null
+++ b/lib/fxp.d.cts
@@ -0,0 +1,772 @@
+/**
+ * Types copied from path-expression-matcher
+ * @version <version>
+ * @updated <date>
+ *
+ * Update this file when path-expression-matcher releases a new version.
+ * Source: https://github.com/NaturalIntelligence/path-expression-matcher
+ */
+
+/**
+ * Options for creating an Expression
+ */
+interface ExpressionOptions {
+  /**
+   * Path separator character
+   * @default '.'
+   */
+  separator?: string;
+}
+
+/**
+ * Parsed segment from an expression pattern
+ */
+interface Segment {
+  type: 'tag' | 'deep-wildcard';
+  tag?: string;
+  namespace?: string;
+  attrName?: string;
+  attrValue?: string;
+  position?: 'first' | 'last' | 'odd' | 'even' | 'nth';
+  positionValue?: number;
+}
+
+/**
+ * Expression - Parses and stores a tag pattern expression.
+ * Patterns are parsed once and stored in an optimized structure for fast matching.
+ *
+ * @example
+ * ```typescript
+ * const expr = new Expression("root.users.user");
+ * const expr2 = new Expression("..user[id]:first");
+ * const expr3 = new Expression("root/users/user", { separator: '/' });
+ * ```
+ *
+ * Pattern Syntax:
+ * - `root.users.user`      — Match exact path
+ * - `..user`               — Match "user" at any depth (deep wildcard)
+ * - `user[id]`             — Match user tag with "id" attribute
+ * - `user[id=123]`         — Match user tag where id="123"
+ * - `user:first`           — Match first occurrence of user tag
+ * - `ns::user`             — Match user tag with namespace "ns"
+ * - `ns::user[id]:first`   — Combine namespace, attribute, and position
+ */
+declare class Expression {
+  readonly pattern: string;
+  readonly separator: string;
+  readonly segments: Segment[];
+
+  constructor(pattern: string, options?: ExpressionOptions);
+
+  get length(): number;
+  hasDeepWildcard(): boolean;
+  hasAttributeCondition(): boolean;
+  hasPositionSelector(): boolean;
+  toString(): string;
+}
+
+// ---------------------------------------------------------------------------
+// MatcherView
+// ---------------------------------------------------------------------------
+
+/**
+ * A lightweight, live read-only view of a Matcher instance.
+ *
+ * Returned by `Matcher.readOnly()`. The same instance is reused across every
+ * callback invocation — no allocation overhead per call. Reads directly from
+ * the parent Matcher's internal state so it always reflects the current parser
+ * position with no copying or freezing.
+ *
+ * Mutation methods (`push`, `pop`, `reset`, `updateCurrent`, `restore`) are
+ * simply absent — misuse is caught at compile time by TypeScript.
+ *
+ * This is the type received by all FXP user callbacks when `jPath: false`.
+ */
+interface MatcherView {
+  readonly separator: string;
+
+  /** Check if current path matches an Expression. */
+  matches(expression: Expression): boolean;
+
+  /** Get current tag name, or `undefined` if path is empty. */
+  getCurrentTag(): string | undefined;
+
+  /** Get current namespace, or `undefined` if not present. */
+  getCurrentNamespace(): string | undefined;
+
+  /** Get attribute value of the current node. */
+  getAttrValue(attrName: string): any;
+
+  /** Check if the current node has a given attribute. */
+  hasAttr(attrName: string): boolean;
+
+  /** Sibling position of the current node (child index in parent). */
+  getPosition(): number;
+
+  /** Occurrence counter of the current tag name at this level. */
+  getCounter(): number;
+
+  /** Number of nodes in the current path. */
+  getDepth(): number;
+
+  /** Current path as a string (e.g. `"root.users.user"`). */
+  toString(separator?: string, includeNamespace?: boolean): string;
+
+  /** Current path as an array of tag names. */
+  toArray(): string[];
+
+  /**
+   * Create a snapshot of the current state.
+   * The snapshot can be passed to the real Matcher.restore() if needed.
+   */
+  snapshot(): MatcherSnapshot;
+}
+
+/**
+ * @deprecated Use {@link MatcherView} instead.
+ * Alias kept for backward compatibility.
+ */
+type ReadonlyMatcher = MatcherView;
+
+/** Internal node structure — exposed via snapshot only. */
+interface PathNode {
+  tag: string;
+  namespace?: string;
+  position: number;
+  counter: number;
+  values?: Record<string, any>;
+}
+
+/** Snapshot of matcher state returned by `snapshot()` and `readOnly().snapshot()`. */
+interface MatcherSnapshot {
+  path: PathNode[];
+  siblingStacks: Map<string, number>[];
+}
+
+/**********************************************************************
+ * 
+ * END of path-expression-matcher relevant typings
+ * 
+ **********************************************************************/
+
+
+
+// jPath: true  → string
+// jPath: false → MatcherView
+type JPathOrMatcher = string | MatcherView;
+type JPathOrExpression = string | Expression;
+
+type ProcessEntitiesOptions = {
+  /**
+   * Whether to enable entity processing
+   * 
+   * Defaults to `true`
+   */
+  enabled?: boolean;
+
+  /**
+   * Maximum size in characters for a single entity definition
+   * 
+   * Defaults to `10000`
+   */
+  maxEntitySize?: number;
+
+  /**
+   * Maximum depth for nested entity references (reserved for future use)
+   * 
+   * Defaults to `10`
+   */
+  maxExpansionDepth?: number;
+
+  /**
+   * Maximum total number of entity expansions allowed
+   * 
+   * Defaults to `1000`
+   */
+  maxTotalExpansions?: number;
+
+  /**
+   * Maximum total expanded content length in characters
+   * 
+   * Defaults to `100000`
+   */
+  maxExpandedLength?: number;
+
+  /**
+   * Maximum number of entities allowed in the XML
+   * 
+   * Defaults to `100`
+   */
+  maxEntityCount?: number;
+
+  /**
+   * Array of tag names where entity replacement is allowed.
+   * If null, entities are replaced in all tags.
+   * 
+   * Defaults to `null`
+   */
+  allowedTags?: string[] | null;
+
+  /**
+   * Custom filter function to determine if entities should be replaced in a tag
+   * 
+   * @param tagName - The name of the current tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @returns `true` to allow entity replacement, `false` to skip
+   * 
+   * Defaults to `null`
+   */
+  tagFilter?: ((tagName: string, jPathOrMatcher: JPathOrMatcher) => boolean) | null;
+};
+
+type EntityDecoderOptions = {
+  setExternalEntities: (entities: Record<string, string>) => void;
+  addInputEntities: (entities: Record<string, string>) => void;
+  reset: () => void;
+  decode: (text: string) => string;
+  setXmlVersion: (version: number) => void;
+}
+
+type X2jOptions = {
+  /**
+   * Preserve the order of tags in resulting JS object
+   * 
+   * Defaults to `false`
+   */
+  preserveOrder?: boolean;
+
+  /**
+   * Give a prefix to the attribute name in the resulting JS object
+   * 
+   * Defaults to '@_'
+   */
+  attributeNamePrefix?: string;
+
+  /**
+   * A name to group all attributes of a tag under, or `false` to disable
+   * 
+   * Defaults to `false`
+   */
+  attributesGroupName?: false | string;
+
+  /**
+   * The name of the next node in the resulting JS
+   * 
+   * Defaults to `#text`
+   */
+  textNodeName?: string;
+
+  /**
+   * Whether to ignore attributes when parsing
+   * 
+   * When `true` - ignores all the attributes
+   * 
+   * When `false` - parses all the attributes
+   * 
+   * When `Array<string | RegExp>` - filters out attributes that match provided patterns
+   * 
+   * When `Function` - calls the function for each attribute and filters out those for which the function returned `true`
+   * 
+   * Defaults to `true`
+   */
+  ignoreAttributes?: boolean | (string | RegExp)[] | ((attrName: string, jPathOrMatcher: JPathOrMatcher) => boolean);
+
+  /**
+   * Whether to remove namespace string from tag and attribute names
+   * 
+   * Defaults to `false`
+   */
+  removeNSPrefix?: boolean;
+
+  /**
+   * Whether to allow attributes without value
+   * 
+   * Defaults to `false`
+   */
+  allowBooleanAttributes?: boolean;
+
+  /**
+   * Whether to parse tag value with `strnum` package
+   * 
+   * Defaults to `true`
+   */
+  parseTagValue?: boolean;
+
+  /**
+   * Whether to parse attribute value with `strnum` package
+   * 
+   * Defaults to `false`
+   */
+  parseAttributeValue?: boolean;
+
+  /**
+   * Whether to remove surrounding whitespace from tag or attribute value
+   * 
+   * Defaults to `true`
+   */
+  trimValues?: boolean;
+
+  /**
+   * Give a property name to set CDATA values to instead of merging to tag's text value
+   * 
+   * Defaults to `false`
+   */
+  cdataPropName?: false | string;
+
+  /**
+   * If set, parse comments and set as this property
+   * 
+   * Defaults to `false`
+   */
+  commentPropName?: false | string;
+
+  /**
+   * Control how tag value should be parsed. Called only if tag value is not empty
+   * 
+   * @param tagName - The name of the tag
+   * @param tagValue - The value of the tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @param hasAttributes - Whether the tag has attributes
+   * @param isLeafNode - Whether the tag is a leaf node
+   * @returns {undefined|null} `undefined` or `null` to set original value.
+   * @returns {unknown} 
+   * 
+   * 1. Different value or value with different data type to set new value.
+   * 2. Same value to set parsed value if `parseTagValue: true`.
+   * 
+   * Defaults to `(tagName, val, jPathOrMatcher, hasAttributes, isLeafNode) => val`
+   */
+  tagValueProcessor?: (tagName: string, tagValue: string, jPathOrMatcher: JPathOrMatcher, hasAttributes: boolean, isLeafNode: boolean) => unknown;
+
+  /**
+   * Control how attribute value should be parsed
+   * 
+   * @param attrName - The name of the attribute
+   * @param attrValue - The value of the attribute
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @returns {undefined|null} `undefined` or `null` to set original value
+   * @returns {unknown}
+   * 
+   * Defaults to `(attrName, val, jPathOrMatcher) => val`
+   */
+  attributeValueProcessor?: (attrName: string, attrValue: string, jPathOrMatcher: JPathOrMatcher) => unknown;
+
+  /**
+   * Options to pass to `strnum` for parsing numbers
+   * 
+   * Defaults to `{ hex: true, leadingZeros: true, eNotation: true }`
+   */
+  numberParseOptions?: strnumOptions;
+
+  /**
+   * Nodes to stop parsing at
+   * 
+   * Accepts string patterns or Expression objects from path-expression-matcher
+   * 
+   * String patterns starting with "*." are automatically converted to ".." for backward compatibility
+   * 
+   * Defaults to `[]`
+   */
+  stopNodes?: JPathOrExpression[];
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+
+  /**
+   * Whether to always create a text node
+   * 
+   * Defaults to `false`
+   */
+  alwaysCreateTextNode?: boolean;
+
+  /**
+   * Determine whether a tag should be parsed as an array
+   * 
+   * @param tagName - The name of the tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @param isLeafNode - Whether the tag is a leaf node
+   * @param isAttribute - Whether this is an attribute
+   * @returns {boolean}
+   * 
+   * Defaults to `() => false`
+   */
+  isArray?: (tagName: string, jPathOrMatcher: JPathOrMatcher, isLeafNode: boolean, isAttribute: boolean) => boolean;
+
+  /**
+   * Whether to process default and DOCTYPE entities
+   * 
+   * When `true` - enables entity processing with default limits
+   * 
+   * When `false` - disables all entity processing
+   * 
+   * When `ProcessEntitiesOptions` - enables entity processing with custom configuration
+   * 
+   * Defaults to `true`
+   */
+  processEntities?: boolean | ProcessEntitiesOptions;
+
+  /**
+   * Whether to process HTML entities
+   * 
+   * Defaults to `false`
+   * @deprecated Use `entityDecoder` instead
+   */
+  htmlEntities?: boolean;
+
+  /**
+   * Custom entity decoder
+   */
+  entityDecoder?: EntityDecoderOptions;
+  /**
+   * Whether to ignore the declaration tag from output
+   * 
+   * Defaults to `false`
+   */
+  ignoreDeclaration?: boolean;
+
+  /**
+   * Whether to ignore Pi tags
+   * 
+   * Defaults to `false`
+   */
+  ignorePiTags?: boolean;
+
+  /**
+   * Transform tag names
+   * 
+   * Defaults to `false`
+   */
+  transformTagName?: ((tagName: string) => string) | false;
+
+  /**
+   * Transform attribute names
+   * 
+   * Defaults to `false`
+   */
+  transformAttributeName?: ((attributeName: string) => string) | false;
+
+  /**
+   * Change the tag name when a different name is returned. Skip the tag from parsed result when false is returned.
+   * Modify `attrs` object to control attributes for the given tag.
+   * 
+   * @param tagName - The name of the tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @param attrs - The attributes object
+   * @returns {string} new tag name.
+   * @returns false to skip the tag
+   * 
+   * Defaults to `(tagName, jPathOrMatcher, attrs) => tagName`
+   */
+  updateTag?: (tagName: string, jPathOrMatcher: JPathOrMatcher, attrs: { [k: string]: string }) => string | boolean;
+
+  /**
+   * If true, adds a Symbol to all object nodes, accessible by {@link XMLParser.getMetaDataSymbol} with
+   * metadata about each the node in the XML file.
+   */
+  captureMetaData?: boolean;
+
+  /**
+   * Maximum number of nested tags
+   * 
+   * Defaults to `100`
+   */
+  maxNestedTags?: number;
+
+  /**
+   * Whether to strictly validate tag names
+   * 
+   * Defaults to `true`
+   */
+  strictReservedNames?: boolean;
+
+  /**
+   * Controls whether callbacks receive jPath as string or Matcher instance
+   * 
+   * When `true` - callbacks receive jPath as string (backward compatible)
+   * 
+   * When `false` - callbacks receive Matcher instance for advanced pattern matching
+   * 
+   * Defaults to `true`
+   */
+  jPath?: boolean;
+
+  /**
+ * Function to sanitize dangerous property names
+ * 
+ * @param name - The name of the property
+ * @returns {string} The sanitized name
+ * 
+ * Defaults to `(name) => __name`
+ */
+  onDangerousProperty?: (name: string) => string;
+};
+
+type strnumOptions = {
+  hex: boolean;
+  leadingZeros: boolean,
+  skipLike?: RegExp,
+  eNotation?: boolean,
+  infinity?: string,
+  unicode?: boolean
+}
+
+type validationOptions = {
+  /**
+   * Whether to allow attributes without value
+   * 
+   * Defaults to `false`
+   */
+  allowBooleanAttributes?: boolean;
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+};
+
+type XmlBuilderOptions = {
+  /**
+   * Give a prefix to the attribute name in the resulting JS object
+   * 
+   * Defaults to '@_'
+   */
+  attributeNamePrefix?: string;
+
+  /**
+   * A name to group all attributes of a tag under, or `false` to disable
+   * 
+   * Defaults to `false`
+   */
+  attributesGroupName?: false | string;
+
+  /**
+   * The name of the next node in the resulting JS
+   * 
+   * Defaults to `#text`
+   */
+  textNodeName?: string;
+
+  /**
+   * Whether to ignore attributes when building
+   * 
+   * When `true` - ignores all the attributes
+   * 
+   * When `false` - builds all the attributes
+   * 
+   * When `Array<string | RegExp>` - filters out attributes that match provided patterns
+   * 
+   * When `Function` - calls the function for each attribute and filters out those for which the function returned `true`
+   * 
+   * Defaults to `true`
+   */
+  ignoreAttributes?: boolean | (string | RegExp)[] | ((attrName: string, jPath: string) => boolean);
+
+  /**
+   * Give a property name to set CDATA values to instead of merging to tag's text value
+   * 
+   * Defaults to `false`
+   */
+  cdataPropName?: false | string;
+
+  /**
+   * If set, parse comments and set as this property
+   * 
+   * Defaults to `false`
+   */
+  commentPropName?: false | string;
+
+  /**
+   * Whether to make output pretty instead of single line
+   * 
+   * Defaults to `false`
+   */
+  format?: boolean;
+
+
+  /**
+   * If `format` is set to `true`, sets the indent string
+   * 
+   * Defaults to `  `
+   */
+  indentBy?: string;
+
+  /**
+   * Give a name to a top-level array
+   * 
+   * Defaults to `undefined`
+   */
+  arrayNodeName?: string;
+
+  /**
+   * Create empty tags for tags with no text value
+   * 
+   * Defaults to `false`
+   */
+  suppressEmptyNode?: boolean;
+
+  /**
+   * Suppress an unpaired tag
+   * 
+   * Defaults to `true`
+   */
+  suppressUnpairedNode?: boolean;
+
+  /**
+   * Don't put a value for boolean attributes
+   * 
+   * Defaults to `true`
+   */
+  suppressBooleanAttributes?: boolean;
+
+  /**
+   * Preserve the order of tags in resulting JS object
+   * 
+   * Defaults to `false`
+   */
+  preserveOrder?: boolean;
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+
+  /**
+   * Nodes to stop parsing at
+   * 
+   * Accepts string patterns or Expression objects from path-expression-matcher
+   * 
+   * Defaults to `[]`
+   */
+  stopNodes?: JPathOrExpression[];
+
+  /**
+   * Control how tag value should be parsed. Called only if tag value is not empty
+   * 
+   * @returns {undefined|null} `undefined` or `null` to set original value.
+   * @returns {unknown} 
+   * 
+   * 1. Different value or value with different data type to set new value.
+   * 2. Same value to set parsed value if `parseTagValue: true`.
+   * 
+   * Defaults to `(tagName, val, jPath, hasAttributes, isLeafNode) => val`
+   */
+  tagValueProcessor?: (name: string, value: unknown) => unknown;
+
+  /**
+   * Control how attribute value should be parsed
+   * 
+   * @param attrName 
+   * @param attrValue 
+   * @param jPath 
+   * @returns {undefined|null} `undefined` or `null` to set original value
+   * @returns {unknown}
+   * 
+   * Defaults to `(attrName, val, jPath) => val`
+   */
+  attributeValueProcessor?: (name: string, value: unknown) => unknown;
+
+  /**
+   * Whether to process default and DOCTYPE entities
+   * 
+   * Defaults to `true`
+   */
+  processEntities?: boolean;
+
+
+  oneListGroup?: boolean;
+
+  /**
+ * Maximum number of nested tags
+ * 
+ * Defaults to `100`
+ */
+  maxNestedTags?: number;
+};
+
+type ESchema = string | object | Array<string | object>;
+
+type ValidationError = {
+  err: {
+    code: string;
+    msg: string,
+    line: number,
+    col: number
+  };
+};
+
+declare class XMLParser {
+  constructor(options?: X2jOptions);
+  parse(xmlData: string | Uint8Array, validationOptions?: validationOptions | boolean): any;
+  /**
+   * Add Entity which is not by default supported by this library
+   * @param entityIdentifier {string} Eg: 'ent' for &ent;
+   * @param entityValue {string} Eg: '\r'
+   * @deprecated Use `entityDecoder` instead
+   */
+  addEntity(entityIdentifier: string, entityValue: string): void;
+
+  /**
+   * Returns a Symbol that can be used to access the {@link XMLMetaData}
+   * property on a node.
+   * 
+   * If Symbol is not available in the environment, an ordinary property is used
+   * and the name of the property is here returned.
+   * 
+   * The XMLMetaData property is only present when {@link X2jOptions.captureMetaData}
+   * is true in the options.
+   */
+  static getMetaDataSymbol(): Symbol;
+}
+
+declare class XMLValidator {
+  static validate(xmlData: string, options?: validationOptions): true | ValidationError;
+}
+/**
+ * @deprecated Use npm package 'fast-xml-builder' instead
+ */
+declare class XMLBuilder {
+  constructor(options?: XmlBuilderOptions);
+  build(jObj: any): string;
+}
+
+
+/**
+ * This object is available on nodes via the symbol {@link XMLParser.getMetaDataSymbol} 
+ * when {@link X2jOptions.captureMetaData} is true.
+ */
+declare interface XMLMetaData {
+  /** The index, if available, of the character where the XML node began in the input stream. */
+  startIndex?: number;
+}
+
+declare namespace fxp {
+  export {
+    XMLParser,
+    XMLValidator,
+    XMLBuilder,
+    XMLMetaData,
+    XmlBuilderOptions,
+    X2jOptions,
+    ESchema,
+    ValidationError,
+    strnumOptions,
+    validationOptions,
+    ProcessEntitiesOptions,
+    Expression,
+    ReadonlyMatcher,
+    MatcherView,
+    JPathOrMatcher,
+    JPathOrExpression,
+    EntityDecoderOptions
+  }
+}
+
+export = fxp;
\ No newline at end of file
diff --git a/spec/typings/typings-test.ts b/spec/typings/typings-test.ts
new file mode 100644
index 0000000..43175b2
--- /dev/null
+++ b/spec/typings/typings-test.ts
@@ -0,0 +1,67 @@
+import {
+    XMLParser,
+    XMLBuilder,
+    XMLValidator,
+    type EntityDecoderOptions,
+    type X2jOptions,
+    type XmlBuilderOptions,
+    type validationOptions,
+} from '../../src/fxp.js';
+
+const parseOpts: X2jOptions = {};
+
+// The parser hands `setXmlVersion` the number it read off `<?xml version="…"?>`.
+const entityDecoder: EntityDecoderOptions = {
+    setExternalEntities: () => {},
+    addInputEntities: () => {},
+    reset: () => {},
+    decode: (text: string) => text,
+    setXmlVersion: (version: number) => {
+        console.log(version.toFixed(1));
+    },
+};
+
+console.log(!!new XMLParser({ entityDecoder }));
+
+// A decoder typed for a string version would compare it against "1.1", which never matches the number it receives.
+type StringVersionAccepted = ((version: string) => void) extends EntityDecoderOptions['setXmlVersion'] ? true : false;
+const stringVersionAccepted: StringVersionAccepted = false;
+
+console.log(stringVersionAccepted);
+
+const XML = `
+    <?xml version="1.0"?>
+    <SomeElement name="parent">
+        <SomeNestedElement name="child"></SomeNestedElement>
+    </SomeElement>
+`;
+
+const parser = new XMLParser(parseOpts);
+const parsed = parser.parse(XML);
+
+console.log(!!parsed);
+
+const buildOpts: XmlBuilderOptions = {};
+
+const builder = new XMLBuilder(buildOpts);
+
+const built = builder.build({
+    any_name: {
+        person: {
+            phone: [
+                15555551313,
+                15555551212
+            ]
+        }
+    }
+});
+
+console.log(!!built);
+
+const validateOpts: validationOptions = {};
+
+const isValid = XMLValidator.validate(built, validateOpts);
+
+console.log(!!isValid);
+
+
diff --git a/src/fxp.d.ts b/src/fxp.d.ts
new file mode 100644
index 0000000..5ba0938
--- /dev/null
+++ b/src/fxp.d.ts
@@ -0,0 +1,754 @@
+/**
+ * Types copied from path-expression-matcher
+ * @version <version>
+ * @updated <date>
+ *
+ * Update this file when path-expression-matcher releases a new version.
+ * Source: https://github.com/NaturalIntelligence/path-expression-matcher
+ */
+
+/**
+ * Options for creating an Expression
+ */
+export interface ExpressionOptions {
+  /**
+   * Path separator character
+   * @default '.'
+   */
+  separator?: string;
+}
+
+/**
+ * Parsed segment from an expression pattern
+ */
+export interface Segment {
+  type: 'tag' | 'deep-wildcard';
+  tag?: string;
+  namespace?: string;
+  attrName?: string;
+  attrValue?: string;
+  position?: 'first' | 'last' | 'odd' | 'even' | 'nth';
+  positionValue?: number;
+}
+
+/**
+ * Expression - Parses and stores a tag pattern expression.
+ * Patterns are parsed once and stored in an optimized structure for fast matching.
+ * 
+ * @example
+ * ```typescript
+ * const expr = new Expression("root.users.user");
+ * const expr2 = new Expression("..user[id]:first");
+ * const expr3 = new Expression("root/users/user", { separator: '/' });
+ * ```
+ * 
+ * Pattern Syntax:
+ * - `root.users.user`      — Match exact path
+ * - `..user`               — Match "user" at any depth (deep wildcard)
+ * - `user[id]`             — Match user tag with "id" attribute
+ * - `user[id=123]`         — Match user tag where id="123"
+ * - `user:first`           — Match first occurrence of user tag
+ * - `ns::user`             — Match user tag with namespace "ns"
+ * - `ns::user[id]:first`   — Combine namespace, attribute, and position
+ */
+export class Expression {
+  readonly pattern: string;
+  readonly separator: string;
+  readonly segments: Segment[];
+
+  constructor(pattern: string, options?: ExpressionOptions);
+
+  get length(): number;
+  hasDeepWildcard(): boolean;
+  hasAttributeCondition(): boolean;
+  hasPositionSelector(): boolean;
+  toString(): string;
+}
+
+// ---------------------------------------------------------------------------
+// MatcherView
+// ---------------------------------------------------------------------------
+
+/**
+ * A lightweight, live read-only view of a Matcher instance.
+ *
+ * Returned by `Matcher.readOnly()`. The same instance is reused across every
+ * callback invocation — no allocation overhead per call. Reads directly from
+ * the parent Matcher's internal state so it always reflects the current parser
+ * position with no copying or freezing.
+ *
+ * Mutation methods (`push`, `pop`, `reset`, `updateCurrent`, `restore`) are
+ * simply absent — misuse is caught at compile time by TypeScript.
+ *
+ * This is the type received by all FXP user callbacks when `jPath: false`.
+ */
+export class MatcherView {
+  readonly separator: string;
+
+  /** Check if current path matches an Expression. */
+  matches(expression: Expression): boolean;
+
+  /** Get current tag name, or `undefined` if path is empty. */
+  getCurrentTag(): string | undefined;
+
+  /** Get current namespace, or `undefined` if not present. */
+  getCurrentNamespace(): string | undefined;
+
+  /** Get attribute value of the current node. */
+  getAttrValue(attrName: string): any;
+
+  /** Check if the current node has a given attribute. */
+  hasAttr(attrName: string): boolean;
+
+  /** Sibling position of the current node (child index in parent). */
+  getPosition(): number;
+
+  /** Occurrence counter of the current tag name at this level. */
+  getCounter(): number;
+
+  /** Number of nodes in the current path. */
+  getDepth(): number;
+
+  /** Current path as a string (e.g. `"root.users.user"`). */
+  toString(separator?: string, includeNamespace?: boolean): string;
+
+  /** Current path as an array of tag names. */
+  toArray(): string[];
+}
+
+/**
+ * @deprecated Use {@link MatcherView} instead.
+ * Alias kept for backward compatibility.
+ */
+export type ReadonlyMatcher = MatcherView;
+
+/** Internal node structure — exposed via snapshot only. */
+export interface PathNode {
+  tag: string;
+  namespace?: string;
+  position: number;
+  counter: number;
+  values?: Record<string, any>;
+}
+
+/** Snapshot of matcher state returned by `snapshot()` and `readOnly().snapshot()`. */
+export interface MatcherSnapshot {
+  path: PathNode[];
+  siblingStacks: Map<string, number>[];
+}
+
+/**********************************************************************
+ * 
+ * END of path-expression-matcher relevant typings
+ * 
+ **********************************************************************/
+
+// jPath: true  → string
+// jPath: false → MatcherView
+type JPathOrMatcher = string | MatcherView;
+type JPathOrExpression = string | Expression;
+
+export type ProcessEntitiesOptions = {
+  /**
+   * Whether to enable entity processing
+   * 
+   * Defaults to `true`
+   */
+  enabled?: boolean;
+
+  /**
+   * Maximum size in characters for a single entity definition
+   * 
+   * Defaults to `10000`
+   */
+  maxEntitySize?: number;
+
+  /**
+   * Maximum depth for nested entity references (reserved for future use)
+   * 
+   * Defaults to `10`
+   */
+  maxExpansionDepth?: number;
+
+  /**
+   * Maximum total number of entity expansions allowed
+   * 
+   * Defaults to `1000`
+   */
+  maxTotalExpansions?: number;
+
+  /**
+   * Maximum total expanded content length in characters
+   * 
+   * Defaults to `100000`
+   */
+  maxExpandedLength?: number;
+
+  /**
+   * Maximum number of entities allowed in the XML
+   * 
+   * Defaults to `100`
+   */
+  maxEntityCount?: number;
+
+  /**
+   * Array of tag names where entity replacement is allowed.
+   * If null, entities are replaced in all tags.
+   * 
+   * Defaults to `null`
+   */
+  allowedTags?: string[] | null;
+
+  /**
+   * Custom filter function to determine if entities should be replaced in a tag
+   * 
+   * @param tagName - The name of the current tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @returns `true` to allow entity replacement, `false` to skip
+   * 
+   * Defaults to `null`
+   */
+  tagFilter?: ((tagName: string, jPathOrMatcher: JPathOrMatcher) => boolean) | null;
+};
+
+export type EntityDecoderOptions = {
+  setExternalEntities: (entities: Record<string, string>) => void;
+  addInputEntities: (entities: Record<string, string>) => void;
+  reset: () => void;
+  decode: (text: string) => string;
+  setXmlVersion: (version: number) => void;
+}
+
+export type X2jOptions = {
+  /**
+   * Preserve the order of tags in resulting JS object
+   * 
+   * Defaults to `false`
+   */
+  preserveOrder?: boolean;
+
+  /**
+   * Give a prefix to the attribute name in the resulting JS object
+   * 
+   * Defaults to '@_'
+   */
+  attributeNamePrefix?: string;
+
+  /**
+   * A name to group all attributes of a tag under, or `false` to disable
+   * 
+   * Defaults to `false`
+   */
+  attributesGroupName?: false | string;
+
+  /**
+   * The name of the next node in the resulting JS
+   * 
+   * Defaults to `#text`
+   */
+  textNodeName?: string;
+
+  /**
+   * Whether to ignore attributes when parsing
+   * 
+   * When `true` - ignores all the attributes
+   * 
+   * When `false` - parses all the attributes
+   * 
+   * When `Array<string | RegExp>` - filters out attributes that match provided patterns
+   * 
+   * When `Function` - calls the function for each attribute and filters out those for which the function returned `true`
+   * 
+   * Defaults to `true`
+   */
+  ignoreAttributes?: boolean | (string | RegExp)[] | ((attrName: string, jPathOrMatcher: JPathOrMatcher) => boolean);
+
+  /**
+   * Whether to remove namespace string from tag and attribute names
+   * 
+   * Defaults to `false`
+   */
+  removeNSPrefix?: boolean;
+
+  /**
+   * Whether to allow attributes without value
+   * 
+   * Defaults to `false`
+   */
+  allowBooleanAttributes?: boolean;
+
+  /**
+   * Whether to parse tag value with `strnum` package
+   * 
+   * Defaults to `true`
+   */
+  parseTagValue?: boolean;
+
+  /**
+   * Whether to parse attribute value with `strnum` package
+   * 
+   * Defaults to `false`
+   */
+  parseAttributeValue?: boolean;
+
+  /**
+   * Whether to remove surrounding whitespace from tag or attribute value
+   * 
+   * Defaults to `true`
+   */
+  trimValues?: boolean;
+
+  /**
+   * Give a property name to set CDATA values to instead of merging to tag's text value
+   * 
+   * Defaults to `false`
+   */
+  cdataPropName?: false | string;
+
+  /**
+   * If set, parse comments and set as this property
+   * 
+   * Defaults to `false`
+   */
+  commentPropName?: false | string;
+
+  /**
+   * Control how tag value should be parsed. Called only if tag value is not empty
+   * 
+   * @param tagName - The name of the tag
+   * @param tagValue - The value of the tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @param hasAttributes - Whether the tag has attributes
+   * @param isLeafNode - Whether the tag is a leaf node
+   * @returns {undefined|null} `undefined` or `null` to set original value.
+   * @returns {unknown} 
+   * 
+   * 1. Different value or value with different data type to set new value.
+   * 2. Same value to set parsed value if `parseTagValue: true`.
+   * 
+   * Defaults to `(tagName, val, jPathOrMatcher, hasAttributes, isLeafNode) => val`
+   */
+  tagValueProcessor?: (tagName: string, tagValue: string, jPathOrMatcher: JPathOrMatcher, hasAttributes: boolean, isLeafNode: boolean) => unknown;
+
+  /**
+   * Control how attribute value should be parsed
+   * 
+   * @param attrName - The name of the attribute
+   * @param attrValue - The value of the attribute
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @returns {undefined|null} `undefined` or `null` to set original value
+   * @returns {unknown}
+   * 
+   * Defaults to `(attrName, val, jPathOrMatcher) => val`
+   */
+  attributeValueProcessor?: (attrName: string, attrValue: string, jPathOrMatcher: JPathOrMatcher) => unknown;
+
+  /**
+   * Options to pass to `strnum` for parsing numbers
+   * 
+   * Defaults to `{ hex: true, leadingZeros: true, eNotation: true }`
+   */
+  numberParseOptions?: strnumOptions;
+
+  /**
+   * Nodes to stop parsing at
+   * 
+   * Accepts string patterns or Expression objects from path-expression-matcher
+   * 
+   * String patterns starting with "*." are automatically converted to ".." for backward compatibility
+   * 
+   * Defaults to `[]`
+   */
+  stopNodes?: JPathOrExpression[];
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+
+  /**
+   * Whether to always create a text node
+   * 
+   * Defaults to `false`
+   */
+  alwaysCreateTextNode?: boolean;
+
+  /**
+   * Determine whether a tag should be parsed as an array
+   * 
+   * @param tagName - The name of the tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @param isLeafNode - Whether the tag is a leaf node
+   * @param isAttribute - Whether this is an attribute
+   * @returns {boolean}
+   * 
+   * Defaults to `() => false`
+   */
+  isArray?: (tagName: string, jPathOrMatcher: JPathOrMatcher, isLeafNode: boolean, isAttribute: boolean) => boolean;
+
+  /**
+   * Whether to process default and DOCTYPE entities
+   * 
+   * When `true` - enables entity processing with default limits
+   * 
+   * When `false` - disables all entity processing
+   * 
+   * When `ProcessEntitiesOptions` - enables entity processing with custom configuration
+   * 
+   * Defaults to `true`
+   */
+  processEntities?: boolean | ProcessEntitiesOptions;
+
+  /**
+   * Whether to process HTML entities
+   * 
+   * Defaults to `false`
+   * @deprecated Use `entityDecoder` instead
+   */
+  htmlEntities?: boolean;
+
+  /**
+   * Custom entity decoder
+   */
+  entityDecoder?: EntityDecoderOptions;
+  /**
+   * Whether to ignore the declaration tag from output
+   * 
+   * Defaults to `false`
+   */
+  ignoreDeclaration?: boolean;
+
+  /**
+   * Whether to ignore Pi tags
+   * 
+   * Defaults to `false`
+   */
+  ignorePiTags?: boolean;
+
+  /**
+   * Transform tag names
+   * 
+   * Defaults to `false`
+   */
+  transformTagName?: ((tagName: string) => string) | false;
+
+  /**
+   * Transform attribute names
+   * 
+   * Defaults to `false`
+   */
+  transformAttributeName?: ((attributeName: string) => string) | false;
+
+  /**
+   * Change the tag name when a different name is returned. Skip the tag from parsed result when false is returned.
+   * Modify `attrs` object to control attributes for the given tag.
+   * 
+   * @param tagName - The name of the tag
+   * @param jPathOrMatcher - The jPath string (if jPath: true) or Matcher instance (if jPath: false)
+   * @param attrs - The attributes object
+   * @returns {string} new tag name.
+   * @returns false to skip the tag
+   * 
+   * Defaults to `(tagName, jPathOrMatcher, attrs) => tagName`
+   */
+  updateTag?: (tagName: string, jPathOrMatcher: JPathOrMatcher, attrs: { [k: string]: string }) => string | boolean;
+
+  /**
+   * If true, adds a Symbol to all object nodes, accessible by {@link XMLParser.getMetaDataSymbol} with
+   * metadata about each the node in the XML file.
+   */
+  captureMetaData?: boolean;
+
+  /**
+   * Maximum number of nested tags
+   * 
+   * Defaults to `100`
+   */
+  maxNestedTags?: number;
+
+  /**
+   * Whether to strictly validate tag names
+   * 
+   * Defaults to `true`
+   */
+  strictReservedNames?: boolean;
+
+  /**
+   * Controls whether callbacks receive jPath as string or Matcher instance
+   * 
+   * When `true` - callbacks receive jPath as string (backward compatible)
+   * 
+   * When `false` - callbacks receive Matcher instance for advanced pattern matching
+   * 
+   * Defaults to `true`
+   */
+  jPath?: boolean;
+
+  /**
+   * Function to sanitize dangerous property names
+   * 
+   * @param name - The name of the property
+   * @returns {string} The sanitized name
+   * 
+   * Defaults to `(name) => __name`
+   */
+  onDangerousProperty?: (name: string) => string;
+};
+
+
+
+export type strnumOptions = {
+  hex: boolean;
+  leadingZeros: boolean,
+  skipLike?: RegExp,
+  eNotation?: boolean,
+  infinity?: string,
+  unicode?: boolean
+}
+
+export type validationOptions = {
+  /**
+   * Whether to allow attributes without value
+   * 
+   * Defaults to `false`
+   */
+  allowBooleanAttributes?: boolean;
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+};
+
+export type XmlBuilderOptions = {
+  /**
+   * Give a prefix to the attribute name in the resulting JS object
+   * 
+   * Defaults to '@_'
+   */
+  attributeNamePrefix?: string;
+
+  /**
+   * A name to group all attributes of a tag under, or `false` to disable
+   * 
+   * Defaults to `false`
+   */
+  attributesGroupName?: false | string;
+
+  /**
+   * The name of the next node in the resulting JS
+   * 
+   * Defaults to `#text`
+   */
+  textNodeName?: string;
+
+  /**
+   * Whether to ignore attributes when building
+   * 
+   * When `true` - ignores all the attributes
+   * 
+   * When `false` - builds all the attributes
+   * 
+   * When `Array<string | RegExp>` - filters out attributes that match provided patterns
+   * 
+   * When `Function` - calls the function for each attribute and filters out those for which the function returned `true`
+   * 
+   * Defaults to `true`
+   */
+  ignoreAttributes?: boolean | (string | RegExp)[] | ((attrName: string, jPath: string) => boolean);
+
+  /**
+   * Give a property name to set CDATA values to instead of merging to tag's text value
+   * 
+   * Defaults to `false`
+   */
+  cdataPropName?: false | string;
+
+  /**
+   * If set, parse comments and set as this property
+   * 
+   * Defaults to `false`
+   */
+  commentPropName?: false | string;
+
+  /**
+   * Whether to make output pretty instead of single line
+   * 
+   * Defaults to `false`
+   */
+  format?: boolean;
+
+
+  /**
+   * If `format` is set to `true`, sets the indent string
+   * 
+   * Defaults to `  `
+   */
+  indentBy?: string;
+
+  /**
+   * Give a name to a top-level array
+   * 
+   * Defaults to `undefined`
+   */
+  arrayNodeName?: string;
+
+  /**
+   * Create empty tags for tags with no text value
+   * 
+   * Defaults to `false`
+   */
+  suppressEmptyNode?: boolean;
+
+  /**
+   * Suppress an unpaired tag
+   * 
+   * Defaults to `true`
+   */
+  suppressUnpairedNode?: boolean;
+
+  /**
+   * Don't put a value for boolean attributes
+   * 
+   * Defaults to `true`
+   */
+  suppressBooleanAttributes?: boolean;
+
+  /**
+   * Preserve the order of tags in resulting JS object
+   * 
+   * Defaults to `false`
+   */
+  preserveOrder?: boolean;
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+
+  /**
+   * Nodes to stop parsing at
+   * 
+   * Accepts string patterns or Expression objects from path-expression-matcher
+   * 
+   * Defaults to `[]`
+   */
+  stopNodes?: JPathOrExpression[];
+
+  /**
+   * Control how tag value should be parsed. Called only if tag value is not empty
+   * 
+   * @returns {undefined|null} `undefined` or `null` to set original value.
+   * @returns {unknown} 
+   * 
+   * 1. Different value or value with different data type to set new value.
+   * 2. Same value to set parsed value if `parseTagValue: true`.
+   * 
+   * Defaults to `(tagName, val, jPath, hasAttributes, isLeafNode) => val`
+   */
+  tagValueProcessor?: (name: string, value: unknown) => unknown;
+
+  /**
+   * Control how attribute value should be parsed
+   * 
+   * @param attrName 
+   * @param attrValue 
+   * @param jPath 
+   * @returns {undefined|null} `undefined` or `null` to set original value
+   * @returns {unknown}
+   * 
+   * Defaults to `(attrName, val, jPath) => val`
+   */
+  attributeValueProcessor?: (name: string, value: unknown) => unknown;
+
+  /**
+   * Whether to process default and DOCTYPE entities
+   * 
+   * Defaults to `true`
+   */
+  processEntities?: boolean;
+
+
+  oneListGroup?: boolean;
+
+  /**
+ * Maximum number of nested tags
+ * 
+ * Defaults to `100`
+ */
+  maxNestedTags?: number;
+};
+
+type ESchema = string | object | Array<string | object>;
+
+export type ValidationError = {
+  err: {
+    code: string;
+    msg: string,
+    line: number,
+    col: number
+  };
+};
+
+export class XMLParser {
+  constructor(options?: X2jOptions);
+
+  parse(xmlData: string | Uint8Array): any;
+  /**
+   * @deprecated The `validationOptions` parameter is deprecated.
+   * Use the `fast-xml-validator` package instead for XML validation.
+   * @see https://www.npmjs.com/package/fast-xml-validator
+   */
+  parse(xmlData: string | Uint8Array, validationOptions: validationOptions | boolean): any;
+  /**
+   * Add Entity which is not by default supported by this library
+   * @param entityIdentifier {string} Eg: 'ent' for &ent;
+   * @param entityValue {string} Eg: '\r'
+   * @deprecated Use `entityDecoder` instead
+   */
+  addEntity(entityIdentifier: string, entityValue: string): void;
+
+  /**
+   * Returns a Symbol that can be used to access the {@link XMLMetaData}
+   * property on a node.
+   * 
+   * If Symbol is not available in the environment, an ordinary property is used
+   * and the name of the property is here returned.
+   * 
+   * The XMLMetaData property is only present when {@link X2jOptions.captureMetaData}
+   * is true in the options.
+   */
+  static getMetaDataSymbol(): Symbol;
+}
+
+/** 
+ * @deprecated Use fast-xml-validator instead
+ * @see https://www.npmjs.com/package/fast-xml-validator
+ */
+export class XMLValidator {
+  static validate(xmlData: string, options?: validationOptions): true | ValidationError;
+}
+/**
+ * @deprecated Use npm package 'fast-xml-builder' instead
+ */
+export class XMLBuilder {
+  constructor(options?: XmlBuilderOptions);
+  build(jObj: any): string;
+}
+
+/**
+ * This object is available on nodes via the symbol {@link XMLParser.getMetaDataSymbol} 
+ * when {@link X2jOptions.captureMetaData} is true.
+ */
+export interface XMLMetaData {
+  /** The index, if available, of the character where the XML node began in the input stream. */
+  startIndex?: number;
+  /** The index, if available, of the character where the XML node ended in the input stream. */
+  endIndex?: number;
+}
\ No newline at end of file