utils/charMapping.js

  1. /**
  2.  * Builder for building a character map.
  3.  */
  4. class CharacterMapBuilder {
  5.   /**
  6.    * Creates a new character map builder.
  7.    */
  8.   constructor() {
  9.     /**
  10.      * Mapping of characters to character codes.
  11.      * @type {Object.<string, number>}
  12.      */
  13.     this.map = {};
  14.   }
  16.   /**
  17.    * Adds a range mapping to the map.
  18.    * @param {string} start Start character.
  19.    * @param {string} end End character.
  20.    * @param {number} base Value corresponding to the start character.
  21.    */
  22.   addRange(start, end, base) {
  23.     const startCode = start.charCodeAt(0);
  24.     const endCode = end.charCodeAt(0);
  26.     for (let code = startCode; code <= endCode; ++code)
  27.       this.map[String.fromCharCode(code)] = code - startCode + base;
  28.   }
  29. }
  31. const charMapping = {
  32.   /**
  33.    * Creates a builder for building a character map.
  34.    * @returns {CharacterMapBuilder} Character map builder.
  35.    */
  36.   createBuilder: () => new CharacterMapBuilder(),
  37. };
  39. export default charMapping;