startsWith.js
974 Bytes
var baseToString = require('../internal/baseToString');
/* Native method references for those with the same name as other `lodash` methods. */
var nativeMin = Math.min;
/**
* Checks if `string` starts with the given target string.
*
* @static
* @memberOf _
* @category String
* @param {string} [string=''] The string to search.
* @param {string} [target] The string to search for.
* @param {number} [position=0] The position to search from.
* @returns {boolean} Returns `true` if `string` starts with `target`, else `false`.
* @example
*
* _.startsWith('abc', 'a');
* // => true
*
* _.startsWith('abc', 'b');
* // => false
*
* _.startsWith('abc', 'b', 1);
* // => true
*/
function startsWith(string, target, position) {
string = baseToString(string);
position = position == null
? 0
: nativeMin(position < 0 ? 0 : (+position || 0), string.length);
return string.lastIndexOf(target, position) == position;
}
module.exports = startsWith;