/* $Id: array.js,v 1.1 2019/07/22 20:51:52 echicken Exp $ */
/**
 * Polyfills for newer Array methods
 * Lifted from MDN https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
 * 
 * This is a legacy-style library and should be loaded with:
 * load('array.js');
 */


if (!Array.from) {
    Array.from = (function () {
        var toStr = Object.prototype.toString;
        var isCallable = function (fn) {
            return typeof fn === 'function' || toStr.call(fn) === '[object Function]';
        };
        var toInteger = function (value) {
            var number = Number(value);
            if (isNaN(number)) return 0;
            if (number === 0 || !isFinite(number)) return number;
            return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number));
        };
        var maxSafeInteger = Math.pow(2, 53) - 1;
        var toLength = function (value) {
            var len = toInteger(value);
            return Math.min(Math.max(len, 0), maxSafeInteger);
        };

        // The length property of the from method is 1.
        return function from(arrayLike/*, mapFn, thisArg */) {
            // 1. Let C be the this value.
            var C = this;

            // 2. Let items be ToObject(arrayLike).
            var items = Object(arrayLike);

            // 3. ReturnIfAbrupt(items).
            if (arrayLike == null) {
                throw new TypeError('Array.from requires an array-like object - not null or undefined');
            }

            // 4. If mapfn is undefined, then let mapping be false.
            var mapFn = arguments.length > 1 ? arguments[1] : void undefined;
            var T;
            if (typeof mapFn !== 'undefined') {
                // 5. else
                // 5. a If IsCallable(mapfn) is false, throw a TypeError exception.
                if (!isCallable(mapFn)) {
                    throw new TypeError('Array.from: when provided, the second argument must be a function');
                }

                // 5. b. If thisArg was supplied, let T be thisArg; else let T be undefined.
                if (arguments.length > 2) T = arguments[2];
            }

            // 10. Let lenValue be Get(items, "length").
            // 11. Let len be ToLength(lenValue).
            var len = toLength(items.length);

            // 13. If IsConstructor(C) is true, then
            // 13. a. Let A be the result of calling the [[Construct]] internal method 
            // of C with an argument list containing the single item len.
            // 14. a. Else, Let A be ArrayCreate(len).
            var A = isCallable(C) ? Object(new C(len)) : new Array(len);

            // 16. Let k be 0.
            var k = 0;
            // 17. Repeat, while k < len… (also steps a - h)
            var kValue;
            while (k < len) {
                kValue = items[k];
                if (mapFn) {
                    A[k] = typeof T === 'undefined' ? mapFn(kValue, k) : mapFn.call(T, kValue, k);
                } else {
                    A[k] = kValue;
                }
                k += 1;
            }
            // 18. Let putStatus be Put(A, "length", len, true).
            A.length = len;
            // 20. Return A.
            return A;
        };
    }());
}

if (!Array.of) {
    Array.of = function() {
        return Array.prototype.slice.call(arguments);
    };
}

if (!Array.prototype.copyWithin) {
    Object.defineProperty(Array.prototype, 'copyWithin', {
        value: function (target, start/*, end*/) {
            // Steps 1-2.
            if (this == null) {
                throw new TypeError('this is null or not defined');
            }

            var O = Object(this);

            // Steps 3-5.
            var len = O.length >>> 0;

            // Steps 6-8.
            var relativeTarget = target >> 0;

            var to = relativeTarget < 0 ?
            Math.max(len + relativeTarget, 0) :
            Math.min(relativeTarget, len);

            // Steps 9-11.
            var relativeStart = start >> 0;

            var from = relativeStart < 0 ?
            Math.max(len + relativeStart, 0) :
            Math.min(relativeStart, len);

            // Steps 12-14.
            var end = arguments[2];
            var relativeEnd = end === undefined ? len : end >> 0;

            var final = relativeEnd < 0 ?
            Math.max(len + relativeEnd, 0) :
            Math.min(relativeEnd, len);

            // Step 15.
            var count = Math.min(final - from, len - to);

            // Steps 16-17.
            var direction = 1;

            if (from < to && to < (from + count)) {
                direction = -1;
                from += count - 1;
                to += count - 1;
            }

            // Step 18.
            while (count > 0) {
                if (from in O) {
                    O[to] = O[from];
                } else {
                    delete O[to];
                }
                from += direction;
                to += direction;
                count--;
            }

            // Step 19.
            return O;
        },
        configurable: true,
        writable: true
    });
}

if (!Array.prototype.fill) {
    Object.defineProperty(Array.prototype, 'fill', {
        value: function (value) {
            // Steps 1-2.
            if (this == null) throw new TypeError('this is null or not defined');

            var O = Object(this);

            // Steps 3-5.
            var len = O.length >>> 0;

            // Steps 6-7.
            var start = arguments[1];
            var relativeStart = start >> 0;

            // Step 8.
            var k = relativeStart < 0 ?
            Math.max(len + relativeStart, 0) :
            Math.min(relativeStart, len);

            // Steps 9-10.
            var end = arguments[2];
            var relativeEnd = end === undefined ?
            len : end >> 0;

            // Step 11.
            var final = relativeEnd < 0 ?
            Math.max(len + relativeEnd, 0) :
            Math.min(relativeEnd, len);

            // Step 12.
            while (k < final) {
                O[k] = value;
                k++;
            }

            // Step 13.
            return O;
        }
    });
}

// https://tc39.github.io/ecma262/#sec-array.prototype.find
if (!Array.prototype.find) {
    Object.defineProperty(Array.prototype, 'find', {
        value: function (predicate) {
            // 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 IsCallable(predicate) is false, throw a TypeError exception.
            if (typeof predicate !== 'function') {
                throw new TypeError('predicate must be a function');
            }

            // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
            var thisArg = arguments[1];

            // 5. Let k be 0.
            var k = 0;

            // 6. Repeat, while k < len
            while (k < len) {
                // a. Let Pk be ! ToString(k).
                // b. Let kValue be ? Get(O, Pk).
                // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
                // d. If testResult is true, return kValue.
                var kValue = o[k];
                if (predicate.call(thisArg, kValue, k, o)) return kValue;
                // e. Increase k by 1.
                k++;
            }

            // 7. Return undefined.
            return undefined;
        },
        configurable: true,
        writable: true
    });
}

// https://tc39.github.io/ecma262/#sec-array.prototype.findindex
if (!Array.prototype.findIndex) {
    Object.defineProperty(Array.prototype, 'findIndex', {
        value: function (predicate) {
            // 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 IsCallable(predicate) is false, throw a TypeError exception.
            if (typeof predicate !== 'function') {
                throw new TypeError('predicate must be a function');
            }

            // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
            var thisArg = arguments[1];

            // 5. Let k be 0.
            var k = 0;

            // 6. Repeat, while k < len
            while (k < len) {
                // a. Let Pk be ! ToString(k).
                // b. Let kValue be ? Get(O, Pk).
                // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
                // d. If testResult is true, return k.
                var kValue = o[k];
                if (predicate.call(thisArg, kValue, k, o)) return k;
                // e. Increase k by 1.
                k++;
            }

            // 7. Return -1.
            return -1;
        },
        configurable: true,
        writable: true
    });
}

// From https://github.com/latusinski/polyfill-array-includes/blob/master/array-includes.js
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;
        }
    });
}
