// Source: https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/includes#Polyfill
// https://tc39.github.io/ecma262/#sec-array.prototype.includes
if (!Array.prototype.includes) {
Object.defineProperty(Array.prototype, 'includes', {
value: function(searchElement, fromIndex) {
if (this == null) {
throw new TypeError('"this" is null or not defined');
}
// 1. Let O be ? ToObject(this value).
var o = Object(this);
// 2. Let len be ? ToLength(? Get(O, "length")).
var len = o.length >>> 0;
// 3. If len is 0, return false.
if (len === 0) {
return false;
}
// 4. Let n be ? ToInteger(fromIndex).
// (If fromIndex is undefined, this step produces the value 0.)
var n = fromIndex | 0;
// 5. If n ≥ 0, then
// a. Let k be n.
// 6. Else n < 0,
// a. Let k be len + n.
// b. If k < 0, let k be 0.
var k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);
function sameValueZero(x, y) {
return x === y || (typeof x === 'number' && typeof y === 'number' && isNaN(x) && isNaN(y));
}
// 7. Repeat, while k < len
while (k < len) {
// a. Let elementK be the result of ? Get(O, ! ToString(k)).
// b. If SameValueZero(searchElement, elementK) is true, return true.
if (sameValueZero(o[k], searchElement)) {
return true;
}
// c. Increase k by 1.
k++;
}
// 8. Return false
return false;
}
});
}