es.string.substr.js
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es.string.substr.js
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	'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, es/no-string-prototype-substr -- 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);
	}
	});