159 lines
3.4 KiB
JavaScript
159 lines
3.4 KiB
JavaScript
// should have a length of 1
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expect(Array.from.length).toBe(1);
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var arr;
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var obj;
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// should make an array from arguments
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function arrayFromArgs() {
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return Array.from(arguments);
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}
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arr = arrayFromArgs('a', 1);
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expect(arr.length).toBe(2);
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expect(arr).toEqual(['a', 1]);
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expect(Array.isArray(arr)).toBe(true);
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// should handle undefined values
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var arrayLike = {0: 'a', 2: 'c', length: 3};
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arr = Array.from(arrayLike);
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expect(arr.length).toBe(3);
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expect(arr).toEqual(['a', undefined, 'c']);
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expect(Array.isArray(arr)).toBe(true);
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// should use a mapFn
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arr = Array.from([{'a': 1}, {'a': 2}], function(item, i) {
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return item.a + i;
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});
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expect(arr).toEqual([1, 3]);
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// should set this in mapFn
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var thisObj = {a: 10};
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arr = Array.from([{'a': 1}, {'a': 2}], function(item, i) {
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return this.a + item.a + i;
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}, thisObj);
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expect(arr).toEqual([11, 13]);
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// should map on array-like object
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arr = Array.from({0: {'a': 5}, length: 1}, function(item, i) {
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return item.a + i;
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});
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expect(arr).toEqual([5]);
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// should throw on bad map fn
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expect(function() {
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Array.from([], null)
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}).toThrow();
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// should make from an array-like object
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var arrayLikeObj = function(len) {
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this.length = len;
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};
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arrayLikeObj.from = Array.from;
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obj = arrayLikeObj.from(['a', 'b', 'c']);
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expect(obj).toHaveLength(3);
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expect(obj).toEqual({0: 'a', 1: 'b', 2: 'c', length: 3});
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// should make from a non-array iterable
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var calledIterator = 0;
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var Iterable = function(len) {
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var self = this;
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self.length = len;
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self[Symbol.iterator] = function*() {
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for (var i = 0; i < self.length; i++) {
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calledIterator++;
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yield self[i];
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}
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};
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};
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var it = new Iterable(3);
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it[0] = 'a';
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it[1] = 'b';
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it[2] = 'c';
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obj = Array.from(it);
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expect(obj).toHaveLength(3);
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expect(obj[0]).toBe('a');
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expect(obj[1]).toBe('b');
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expect(obj[2]).toBe('c');
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expect(calledIterator).toBe(3);
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// should make from a sub-classed array
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var length = 0;
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var constructorCounter = 0;
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var lengthSetCounter = 0;
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var lengthGetCounter = 0;
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class MyArray extends Array {
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constructor(v) {
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super();
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constructorCounter++;
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expect(v).toBeUndefined();
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}
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set length(v) {
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lengthSetCounter++;
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length = v;
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}
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get length() {
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lengthGetCounter++;
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return length;
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}
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}
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var ma = MyArray.from(['a', 'b']);
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expect(ma).toBeInstanceOf(MyArray);
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expect(constructorCounter).toBe(1);
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expect(lengthSetCounter).toBe(1);
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expect(lengthGetCounter).toBe(0);
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expect(ma).toContain('0');
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expect(ma).toContain('1');
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expect(ma).not.toContain('length');
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expect(ma[0]).toBe('a');
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expect(ma[1]).toBe('b');
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expect(ma).toHaveLength(2);
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// should make from a sub-classed array without iterable
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length = 0;
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constructorCounter = 0;
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lengthSetCounter = 0;
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lengthGetCounter = 0;
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class MyArray2 extends MyArray {
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constructor(v) {
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super();
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constructorCounter++;
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expect(v).toBe(2);
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}
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};
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MyArray2.prototype[Symbol.iterator] = undefined;
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class MyArray3 extends Array {
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constructor(v) {
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super();
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this.length = v;
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}
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}
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MyArray3.prototype[Symbol.iterator] = undefined;
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var ma3 = new MyArray3(2);
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ma3[0] = 'a';
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ma3[1] = 'b';
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ma = MyArray2.from(ma3);
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expect(ma).toBeInstanceOf(MyArray2);
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expect(constructorCounter).toBe(2);
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expect(lengthSetCounter).toBe(1);
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expect(lengthGetCounter).toBe(0);
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expect(ma).toContain('0');
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expect(ma).toContain('1');
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expect(ma).not.toContain('length');
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expect(ma[0]).toBe('a');
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expect(ma[1]).toBe('b');
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expect(ma).toHaveLength(2);
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