RegExp.escape-toSearch.js

/**
 *  The tool named `toSearch` is a helper method nailed statically
 *  onto the `RegExp` constructor/namespace. It does support a way
 *  of building search terms/strings at runtime.
 *  In order to accomplish this task `RegExp.toSearch` makes use of
 *  `RegExp.escape` that's implementation takes into account that
 *  such strings might partly contain `RegExp` control characters
 *  which are not supposed to be read by the `RegExp` compiler as
 *  exactly this control characters but rather shall be an integral
 *  part of such above mentioned searches.
 *  `RegExp.toSearch` then additionally assures a "forgiving" or
 *  loose handling of whitespace sequences on both sides, the string
 *  which is source of the to be build search term as well as of all
 *  strings that are going to be searched.
 */
(function (Object, RegExp) {

  'use strict';

  function escape/*RegexPattern*/(value) {
    return String(value).replace(/[^$.*+?|(){}[\]\\]/g, '\\$&');
  }
  // escape.toString = () => 'escape() { [native code] }';

  Object.defineProperty(RegExp, 'escape', {
    configurable: true,
    writable: true,
    value: escape,
  });

  const classPatternWhiteSpaceSequence = ['[',

    //  http://es5.github.com/#WhiteSpace
    //  http://www.sql-und-xml.de/unicode-database/ogham.html
    //   - \u1680 :: OGHAM SPACE MARK
    //   - " ".charCodeAt(0).toString(16)

    '\\x09\\x0A\\x0B\\x0C\\x0D\\x20\\xA0\\u1680\\u180E\\u2000',
    '\\u2001\\u2002\\u2003\\u2004\\u2005\\u2006\\u2007\\u2008',
    '\\u2009\\u200A\\u202F\\u205F\\u3000\\u2028\\u2029\\uFEFF',

  ']+'].join('');

  function toSearch/*Pattern*/(value) {
    return escape(value)
      .replace(
        RegExp(classPatternWhiteSpaceSequence, 'g'),
        classPatternWhiteSpaceSequence,
      );
  }
  // toSearch.toString = () => 'toSearch() { [native code] }';

  // function toSearch/*Pattern*/(value) {
  //   return escape(value).replace(/\s+/g, '\\s+');
  // }
  // // toSearch.toString = () => 'toSearch() { [native code] }';

  Object.defineProperty(RegExp, 'toSearch', {
    configurable: true,
    writable: true,
    value: toSearch,
  });

}(Object, RegExp));