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biomedjs/node_modules/lodash/string/repeat.js

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2015-04-20 05:31:12 -04:00
var baseToString = require('../internal/baseToString');
/** Native method references. */
var floor = Math.floor;
/* Native method references for those with the same name as other `lodash` methods. */
var nativeIsFinite = global.isFinite;
/**
* Repeats the given string `n` times.
*
* @static
* @memberOf _
* @category String
* @param {string} [string=''] The string to repeat.
* @param {number} [n=0] The number of times to repeat the string.
* @returns {string} Returns the repeated string.
* @example
*
* _.repeat('*', 3);
* // => '***'
*
* _.repeat('abc', 2);
* // => 'abcabc'
*
* _.repeat('abc', 0);
* // => ''
*/
function repeat(string, n) {
var result = '';
string = baseToString(string);
n = +n;
if (n < 1 || !string || !nativeIsFinite(n)) {
return result;
}
// Leverage the exponentiation by squaring algorithm for a faster repeat.
// See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
do {
if (n % 2) {
result += string;
}
n = floor(n / 2);
string += string;
} while (n);
return result;
}
module.exports = repeat;