xml-lite/lib/repeat-string.js

maintaining xml in pure javascript (IN BOTH NODE.JS & BROWSERS)

'use strict';
/**
 * repeat-string module
 * @module repeat-string
 * @see module:index
 */

let res = '';
let cache;

/**
 * Repeat the given `string` the specified `number`
 * of times.
 *
 * **Example:**
 *
 * ```js
 * var repeat = require('repeat-string');
 * repeat('A', 5);
 * //=> AAAAA
 * ```
 *
 * @param {String} `string` The string to repeat
 * @param {Number} `number` The number of times to repeat the string
 * @return {String} Repeated string
 * @api public
 */

module.exports = (str, num) => {
  str = String(str);

  // cover common, quick use cases
  if (num === 1) return str;
  if (num === 2) return str + str;

  const max = str.length * num;
  if (cache !== str || typeof cache === 'undefined') {
    cache = str;
    res = '';
  }

  while (max > res.length && num > 0) {
    if (num & 1) {
      res += str;
    }

    num >>= 1;
    if (!num) break;
    str += str;
  }

  return res.substr(0, max);
};