token_tree.js

import HTMLRenderer from './html_renderer.js';

/** @typedef {{scope?: string, language?: string, children: Node[]} | string} Node */
/** @typedef {{scope?: string, language?: string, children: Node[]} } DataNode */
/** @typedef {import('highlight.js').Emitter} Emitter */
/**  */

/** @returns {DataNode} */
const newNode = (opts = {}) => {
  /** @type DataNode */
  const result = { children: [] };
  Object.assign(result, opts);
  return result;
};

class TokenTree {
  constructor() {
    /** @type DataNode */
    this.rootNode = newNode();
    this.stack = [this.rootNode];
  }

  get top() {
    return this.stack[this.stack.length - 1];
  }

  get root() { return this.rootNode; }

  /** @param {Node} node */
  add(node) {
    this.top.children.push(node);
  }

  /** @param {string} scope */
  openNode(scope) {
    /** @type Node */
    const node = newNode({ scope });
    this.add(node);
    this.stack.push(node);
  }

  closeNode() {
    if (this.stack.length > 1) {
      return this.stack.pop();
    }
    // eslint-disable-next-line no-undefined
    return undefined;
  }

  closeAllNodes() {
    while (this.closeNode());
  }

  toJSON() {
    return JSON.stringify(this.rootNode, null, 4);
  }

  /**
   * @typedef { import("./html_renderer").Renderer } Renderer
   * @param {Renderer} builder
   */
  walk(builder) {
    // this does not
    return this.constructor._walk(builder, this.rootNode);
    // this works
    // return TokenTree._walk(builder, this.rootNode);
  }

  /**
   * @param {Renderer} builder
   * @param {Node} node
   */
  static _walk(builder, node) {
    if (typeof node === "string") {
      builder.addText(node);
    } else if (node.children) {
      builder.openNode(node);
      node.children.forEach((child) => this._walk(builder, child));
      builder.closeNode(node);
    }
    return builder;
  }

  /**
   * @param {Node} node
   */
  static _collapse(node) {
    if (typeof node === "string") return;
    if (!node.children) return;

    if (node.children.every(el => typeof el === "string")) {
      // node.text = node.children.join("");
      // delete node.children;
      node.children = [node.children.join("")];
    } else {
      node.children.forEach((child) => {
        TokenTree._collapse(child);
      });
    }
  }
}

/**
  Currently this is all private API, but this is the minimal API necessary
  that an Emitter must implement to fully support the parser.

  Minimal interface:

  - addText(text)
  - __addSublanguage(emitter, subLanguageName)
  - startScope(scope)
  - endScope()
  - finalize()
  - toHTML()

*/

/**
 * @implements {Emitter}
 */
export default class TokenTreeEmitter extends TokenTree {
  /**
   * @param {*} options
   */
  constructor(options) {
    super();
    this.options = options;
  }

  /**
   * @param {string} text
   */
  addText(text) {
    if (text === "") { return; }

    this.add(text);
  }

  /** @param {string} scope */
  startScope(scope) {
    this.openNode(scope);
  }

  endScope() {
    this.closeNode();
  }

  /**
   * @param {Emitter & {root: DataNode}} emitter
   * @param {string} name
   */
  __addSublanguage(emitter, name) {
    /** @type DataNode */
    const node = emitter.root;
    if (name) node.scope = `language:${name}`;

    this.add(node);
  }

  toHTML() {
    const renderer = new HTMLRenderer(this, this.options);
    return renderer.value();
  }

  finalize() {
    this.closeAllNodes();
    return true;
  }
}