core-js/modules/es6.string.starts-with.js

Standard library

'use strict';
var $def     = require('./$.def')
  , toLength = require('./$.to-length')
  , context  = require('./$.string-context');

// should throw error on regex
$def($def.P + $def.F * !require('./$.fails')(function(){ 'q'.startsWith(/./); }), 'String', {
  // 21.1.3.18 String.prototype.startsWith(searchString [, position ])
  startsWith: function startsWith(searchString /*, position = 0 */){
    var that   = context(this, searchString, 'startsWith')
      , index  = toLength(Math.min(arguments[1], that.length))
      , search = String(searchString);
    return that.slice(index, index + search.length) === search;
  }
});