'use strict';
|
var $ = require('../internals/export');
|
var uncurryThis = require('../internals/function-uncurry-this');
|
var requireObjectCoercible = require('../internals/require-object-coercible');
|
var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
|
var toString = require('../internals/to-string');
|
|
var stringSlice = uncurryThis(''.slice);
|
var max = Math.max;
|
var min = Math.min;
|
|
// eslint-disable-next-line unicorn/prefer-string-slice -- required for testing
|
var FORCED = !''.substr || 'ab'.substr(-1) !== 'b';
|
|
// `String.prototype.substr` method
|
// https://tc39.es/ecma262/#sec-string.prototype.substr
|
$({ target: 'String', proto: true, forced: FORCED }, {
|
substr: function substr(start, length) {
|
var that = toString(requireObjectCoercible(this));
|
var size = that.length;
|
var intStart = toIntegerOrInfinity(start);
|
var intLength, intEnd;
|
if (intStart === Infinity) intStart = 0;
|
if (intStart < 0) intStart = max(size + intStart, 0);
|
intLength = length === undefined ? size : toIntegerOrInfinity(length);
|
if (intLength <= 0 || intLength === Infinity) return '';
|
intEnd = min(intStart + intLength, size);
|
return intStart >= intEnd ? '' : stringSlice(that, intStart, intEnd);
|
}
|
});
|
