pollyfills.js

/*
 These polyfills came directly from the ES Specification itself
 Contained within:
	- Object.assign
	- Array.prototype.find
*/
if (typeof Object.assign !== 'function') {
  (function () {
    Object.assign = function (target) {
      if (target === undefined || target === null) {
        throw new TypeError('Cannot convert undefined or null to object');
      }

      var output = Object(target);
      for (var index = 1; index < arguments.length; index++) {
        var source = arguments[index];
        if (source !== undefined && source !== null) {
          for (var nextKey in source) {
            if (source.hasOwnProperty(nextKey)) {
              output[nextKey] = source[nextKey];
            }
          }
        }
      }
      return output;
    };
  })();
}

if (!Array.prototype.find) {
  Object.defineProperty(Array.prototype, 'find', {
    value: function (predicate) {
      if (this === null) {
        throw new TypeError('Array.prototype.find called on null or undefined');
      }
      if (typeof predicate !== 'function') {
        throw new TypeError('predicate must be a function');
      }
      var list = Object(this);
      var length = list.length >>> 0;
      var thisArg = arguments[1];
      var value;

      for (var i = 0; i < length; i++) {
        value = list[i];
        if (predicate.call(thisArg, value, i, list)) {
          return value;
        }
      }
      return undefined;
    }
  });
}

if (!Array.prototype.findIndex) {
  Object.defineProperty(Array.prototype, 'findIndex', {
    value: function (predicate, thisArg) {
      if (this === null) {
        throw new TypeError('Array.prototype.find called on null or undefined');
      }
      if (typeof predicate !== 'function') {
        throw new TypeError('predicate must be a function');
      }
      var list = Object(this);
      var length = list.length >>> 0;
      var value;

      for (var i = 0; i < length; i++) {
        value = list[i];
        if (predicate.call(thisArg, value, i, list)) {
          return i;
        }
      }
      return -1;
    }
  });
}

// Spelled incorrectly intentionally (backwards compatibility).
export function pollyfillElementsFromPoint() {
  if (document.elementsFromPoint) return document.elementsFromPoint;
  if (document.msElementsFromPoint) return document.msElementsFromPoint;

  var usePointer = (function () {
    var element = document.createElement('x');
    element.style.cssText = 'pointer-events:auto';
    return element.style.pointerEvents === 'auto';
  })();

  var cssProp = usePointer ? 'pointer-events' : 'visibility';
  var cssDisableVal = usePointer ? 'none' : 'hidden';

  var style = document.createElement('style');
  style.innerHTML = usePointer
    ? '* { pointer-events: all }'
    : '* { visibility: visible }';

  return function (x, y) {
    var current, i, d;
    var elements = [];
    var previousPointerEvents = [];

    // startup
    document.head.appendChild(style);

    while (
      (current = document.elementFromPoint(x, y)) &&
      elements.indexOf(current) === -1
    ) {
      // push the element and its current style
      elements.push(current);

      previousPointerEvents.push({
        value: current.style.getPropertyValue(cssProp),
        priority: current.style.getPropertyPriority(cssProp)
      });

      // add "pointer-events: none", to get to the underlying element
      current.style.setProperty(cssProp, cssDisableVal, 'important');
    }

    // Due to negative index, documentElement could actually not be the last,
    // so we'll simply move it to the end
    if (elements.indexOf(document.documentElement) < elements.length - 1) {
      elements.splice(elements.indexOf(document.documentElement), 1);
      elements.push(document.documentElement);
    }

    // restore the previous pointer-events values
    for (
      i = previousPointerEvents.length;
      !!(d = previousPointerEvents[--i]);

    ) {
      elements[i].style.setProperty(
        cssProp,
        d.value ? d.value : '',
        d.priority
      );
    }

    // teardown;
    document.head.removeChild(style);

    return elements;
  };
}

if (typeof window.addEventListener === 'function') {
  document.elementsFromPoint = pollyfillElementsFromPoint();
}

if (!Array.prototype.includes) {
  Object.defineProperty(Array.prototype, 'includes', {
    value: function (searchElement) {
      var O = Object(this);
      var len = parseInt(O.length, 10) || 0;
      if (len === 0) {
        return false;
      }
      var n = parseInt(arguments[1], 10) || 0;
      var k;
      if (n >= 0) {
        k = n;
      } else {
        k = len + n;
        if (k < 0) {
          k = 0;
        }
      }
      var currentElement;
      while (k < len) {
        currentElement = O[k];
        if (
          searchElement === currentElement ||
          (searchElement !== searchElement && currentElement !== currentElement)
        ) {
          // NaN !== NaN
          return true;
        }
        k++;
      }
      return false;
    }
  });
}

// Production steps of ECMA-262, Edition 5, 15.4.4.17
// Reference: http://es5.github.io/#x15.4.4.17
if (!Array.prototype.some) {
  Object.defineProperty(Array.prototype, 'some', {
    value: function (fun) {
      if (this == null) {
        throw new TypeError('Array.prototype.some called on null or undefined');
      }

      if (typeof fun !== 'function') {
        throw new TypeError();
      }

      var t = Object(this);
      var len = t.length >>> 0;

      var thisArg = arguments.length >= 2 ? arguments[1] : void 0;
      for (var i = 0; i < len; i++) {
        if (i in t && fun.call(thisArg, t[i], i, t)) {
          return true;
        }
      }

      return false;
    }
  });
}

if (!Array.from) {
  Object.defineProperty(Array, 'from', {
    value: (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 (!String.prototype.includes) {
  String.prototype.includes = function (search, start) {
    if (typeof start !== 'number') {
      start = 0;
    }
    if (start + search.length > this.length) {
      return false;
    } else {
      return this.indexOf(search, start) !== -1;
    }
  };
}

// @see https://github.com/jonathantneal/array-flat-polyfill/blob/master/src/polyfill-flat.js
if (!Array.prototype.flat) {
  Object.defineProperty(Array.prototype, 'flat', {
    configurable: true,
    value: function flat() {
      var depth = isNaN(arguments[0]) ? 1 : Number(arguments[0]);

      return depth
        ? Array.prototype.reduce.call(
            this,
            function (acc, cur) {
              if (Array.isArray(cur)) {
                acc.push.apply(acc, flat.call(cur, depth - 1));
              } else {
                acc.push(cur);
              }

              return acc;
            },
            []
          )
        : Array.prototype.slice.call(this);
    },
    writable: true
  });
}

// linked from MDN docs on isConnected
// @see https://gist.github.com/eligrey/f109a6d0bf4efe3461201c3d7b745e8f
if (window.Node && !('isConnected' in window.Node.prototype)) {
  Object.defineProperty(window.Node.prototype, 'isConnected', {
    get() {
      return (
        !this.ownerDocument ||
        !(
          this.ownerDocument.compareDocumentPosition(this) &
          this.DOCUMENT_POSITION_DISCONNECTED
        )
      );
    }
  });
}