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- 'use strict';
- var res = '';
- var cache;
- module.exports = repeat;
- function repeat(str, num) {
- if (typeof str !== 'string') {
- throw new TypeError('expected a string');
- }
-
- if (num === 1) return str;
- if (num === 2) return str + str;
- var max = str.length * num;
- if (cache !== str || typeof cache === 'undefined') {
- cache = str;
- res = '';
- } else if (res.length >= max) {
- return res.substr(0, max);
- }
- while (max > res.length && num > 1) {
- if (num & 1) {
- res += str;
- }
- num >>= 1;
- str += str;
- }
- res += str;
- res = res.substr(0, max);
- return res;
- }
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