polyfills.js

/* eslint-disable no-extend-native */

if (!String.prototype.padStart) {
    String.prototype.padStart = function padStart(targetLength, padString) {
        targetLength = targetLength >> 0;

        padString = String(padString || ' ');
        if (this.length > targetLength) {
            return String(this);
        } else {
            targetLength = targetLength - this.length;
            if (targetLength > padString.length) {
                padString += padString.repeat(targetLength / padString.length);
            }
            return padString.slice(0, targetLength) + String(this);
        }
    };
}

// https://tc39.github.io/ecma262/#sec-array.prototype.includes
if (!Array.prototype.includes) {
    Object.defineProperty(Array.prototype, 'includes', {
        value: function (searchElement, fromIndex) {
            // 1. Let O be ? ToObject(this value).
            if (this == null) {
                throw new TypeError('"this" is null or not defined');
            }

            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.
                // c. Increase k by 1.
                if (sameValueZero(o[k], searchElement)) {
                    return true;
                }
                k++;
            }

            // 8. Return false
            return false;
        },
    });
}

// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries#Polyfill
if (!Object.entries) {
    Object.entries = function (obj) {
        var ownProps = Object.keys(obj),
            i = ownProps.length,
            resArray = new Array(i); // preallocate the Array
        while (i--) resArray[i] = [ownProps[i], obj[ownProps[i]]];

        return resArray;
    };
}