1  /*!
 2   * repeat-string <https://github.com/jonschlinkert/repeat-string>
 3   *
 4   * Copyright (c) 2014-2015, Jon Schlinkert.
 5   * Licensed under the MIT License.
 6   */
 7  
 8  'use strict';
 9  
10  /**
11   * Results cache
12   */
13  
14  var res = '';
15  var cache;
16  
17  /**
18   * Expose `repeat`
19   */
20  
21  module.exports = repeat;
22  
23  /**
24   * Repeat the given `string` the specified `number`
25   * of times.
26   *
27   * **Example:**
28   *
29   * ```js
30   * var repeat = require('repeat-string');
31   * repeat('A', 5);
32   * //=> AAAAA
33   * ```
34   *
35   * @param {String} `string` The string to repeat
36   * @param {Number} `number` The number of times to repeat the string
37   * @return {String} Repeated string
38   * @api public
39   */
40  
41  function repeat(str, num) {
42    if (typeof str !== 'string') {
43      throw new TypeError('expected a string');
44    }
45  
46    // cover common, quick use cases
47    if (num === 1) return str;
48    if (num === 2) return str + str;
49  
50    var max = str.length * num;
51    if (cache !== str || typeof cache === 'undefined') {
52      cache = str;
53      res = '';
54    } else if (res.length >= max) {
55      return res.substr(0, max);
56    }
57  
58    while (max > res.length && num > 1) {
59      if (num & 1) {
60        res += str;
61      }
62  
63      num >>= 1;
64      str += str;
65    }
66  
67    res += str;
68    res = res.substr(0, max);
69    return res;
70  }