mirror of https://github.com/jkjoy/sunpeiwen.git
71 lines
1.2 KiB
JavaScript
71 lines
1.2 KiB
JavaScript
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/*!
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* repeat-string <https://github.com/jonschlinkert/repeat-string>
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*
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* Copyright (c) 2014-2015, Jon Schlinkert.
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* Licensed under the MIT License.
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*/
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'use strict';
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/**
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* Results cache
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*/
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var res = '';
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var cache;
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/**
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* Expose `repeat`
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*/
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module.exports = repeat;
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/**
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* Repeat the given `string` the specified `number`
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* of times.
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*
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* **Example:**
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*
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* ```js
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* var repeat = require('repeat-string');
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* repeat('A', 5);
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* //=> AAAAA
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* ```
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*
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* @param {String} `string` The string to repeat
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* @param {Number} `number` The number of times to repeat the string
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* @return {String} Repeated string
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* @api public
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*/
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function repeat(str, num) {
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if (typeof str !== 'string') {
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throw new TypeError('expected a string');
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}
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// cover common, quick use cases
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if (num === 1) return str;
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if (num === 2) return str + str;
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var max = str.length * num;
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if (cache !== str || typeof cache === 'undefined') {
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cache = str;
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res = '';
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} else if (res.length >= max) {
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return res.substr(0, max);
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}
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while (max > res.length && num > 1) {
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if (num & 1) {
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res += str;
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}
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num >>= 1;
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str += str;
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}
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res += str;
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res = res.substr(0, max);
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return res;
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}
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