/
arrays.js
229 lines (186 loc) · 11.2 KB
/
arrays.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
(function() {
module('Arrays');
test('first', function() {
equal(_.first([1,2,3]), 1, 'can pull out the first element of an array');
equal(_([1, 2, 3]).first(), 1, 'can perform OO-style "first()"');
equal(_.first([1,2,3], 0).join(', '), '', 'can pass an index to first');
equal(_.first([1,2,3], 2).join(', '), '1, 2', 'can pass an index to first');
equal(_.first([1,2,3], 5).join(', '), '1, 2, 3', 'can pass an index to first');
var result = (function(){ return _.first(arguments); })(4, 3, 2, 1);
equal(result, 4, 'works on an arguments object.');
result = _.map([[1,2,3],[1,2,3]], _.first);
equal(result.join(','), '1,1', 'works well with _.map');
result = (function() { return _.take([1,2,3], 2); })();
equal(result.join(','), '1,2', 'aliased as take');
equal(_.first(null), undefined, 'handles nulls');
strictEqual(_.first([1, 2, 3], -1).length, 0);
});
test('rest', function() {
var numbers = [1, 2, 3, 4];
equal(_.rest(numbers).join(', '), '2, 3, 4', 'working rest()');
equal(_.rest(numbers, 0).join(', '), '1, 2, 3, 4', 'working rest(0)');
equal(_.rest(numbers, 2).join(', '), '3, 4', 'rest can take an index');
var result = (function(){ return _(arguments).tail(); })(1, 2, 3, 4);
equal(result.join(', '), '2, 3, 4', 'aliased as tail and works on arguments object');
result = _.map([[1,2,3],[1,2,3]], _.rest);
equal(_.flatten(result).join(','), '2,3,2,3', 'works well with _.map');
result = (function(){ return _(arguments).drop(); })(1, 2, 3, 4);
equal(result.join(', '), '2, 3, 4', 'aliased as drop and works on arguments object');
});
test('initial', function() {
equal(_.initial([1,2,3,4,5]).join(', '), '1, 2, 3, 4', 'working initial()');
equal(_.initial([1,2,3,4],2).join(', '), '1, 2', 'initial can take an index');
var result = (function(){ return _(arguments).initial(); })(1, 2, 3, 4);
equal(result.join(', '), '1, 2, 3', 'initial works on arguments object');
result = _.map([[1,2,3],[1,2,3]], _.initial);
equal(_.flatten(result).join(','), '1,2,1,2', 'initial works with _.map');
});
test('last', function() {
equal(_.last([1,2,3]), 3, 'can pull out the last element of an array');
equal(_.last([1,2,3], 0).join(', '), '', 'can pass an index to last');
equal(_.last([1,2,3], 2).join(', '), '2, 3', 'can pass an index to last');
equal(_.last([1,2,3], 5).join(', '), '1, 2, 3', 'can pass an index to last');
var result = (function(){ return _(arguments).last(); })(1, 2, 3, 4);
equal(result, 4, 'works on an arguments object');
result = _.map([[1,2,3],[1,2,3]], _.last);
equal(result.join(','), '3,3', 'works well with _.map');
equal(_.last(null), undefined, 'handles nulls');
strictEqual(_.last([1, 2, 3], -1).length, 0);
});
test('compact', function() {
equal(_.compact([0, 1, false, 2, false, 3]).length, 3, 'can trim out all falsy values');
var result = (function(){ return _.compact(arguments).length; })(0, 1, false, 2, false, 3);
equal(result, 3, 'works on an arguments object');
});
test('flatten', function() {
var list = [1, [2], [3, [[[4]]]]];
deepEqual(_.flatten(list), [1,2,3,4], 'can flatten nested arrays');
deepEqual(_.flatten(list, true), [1,2,3,[[[4]]]], 'can shallowly flatten nested arrays');
var result = (function(){ return _.flatten(arguments); })(1, [2], [3, [[[4]]]]);
deepEqual(result, [1,2,3,4], 'works on an arguments object');
list = [[1], [2], [3], [[4]]];
deepEqual(_.flatten(list, true), [1, 2, 3, [4]], 'can shallowly flatten arrays containing only other arrays');
});
test('without', function() {
var list = [1, 2, 1, 0, 3, 1, 4];
equal(_.without(list, 0, 1).join(', '), '2, 3, 4', 'can remove all instances of an object');
var result = (function(){ return _.without(arguments, 0, 1); })(1, 2, 1, 0, 3, 1, 4);
equal(result.join(', '), '2, 3, 4', 'works on an arguments object');
list = [{one : 1}, {two : 2}];
ok(_.without(list, {one : 1}).length == 2, 'uses real object identity for comparisons.');
ok(_.without(list, list[0]).length == 1, 'ditto.');
});
test('uniq', function() {
var list = [1, 2, 1, 3, 1, 4];
equal(_.uniq(list).join(', '), '1, 2, 3, 4', 'can find the unique values of an unsorted array');
list = [1, 1, 1, 2, 2, 3];
equal(_.uniq(list, true).join(', '), '1, 2, 3', 'can find the unique values of a sorted array faster');
list = [{name:'moe'}, {name:'curly'}, {name:'larry'}, {name:'curly'}];
var iterator = function(value) { return value.name; };
equal(_.map(_.uniq(list, false, iterator), iterator).join(', '), 'moe, curly, larry', 'can find the unique values of an array using a custom iterator');
equal(_.map(_.uniq(list, iterator), iterator).join(', '), 'moe, curly, larry', 'can find the unique values of an array using a custom iterator without specifying whether array is sorted');
iterator = function(value) { return value +1; };
list = [1, 2, 2, 3, 4, 4];
equal(_.uniq(list, true, iterator).join(', '), '1, 2, 3, 4', 'iterator works with sorted array');
var result = (function(){ return _.uniq(arguments); })(1, 2, 1, 3, 1, 4);
equal(result.join(', '), '1, 2, 3, 4', 'works on an arguments object');
});
test('intersection', function() {
var stooges = ['moe', 'curly', 'larry'], leaders = ['moe', 'groucho'];
equal(_.intersection(stooges, leaders).join(''), 'moe', 'can take the set intersection of two arrays');
equal(_(stooges).intersection(leaders).join(''), 'moe', 'can perform an OO-style intersection');
var result = (function(){ return _.intersection(arguments, leaders); })('moe', 'curly', 'larry');
equal(result.join(''), 'moe', 'works on an arguments object');
var theSixStooges = ['moe', 'moe', 'curly', 'curly', 'larry', 'larry'];
equal(_.intersection(theSixStooges, leaders).join(''), 'moe', 'returns a duplicate-free array');
});
test('union', function() {
var result = _.union([1, 2, 3], [2, 30, 1], [1, 40]);
equal(result.join(' '), '1 2 3 30 40', 'takes the union of a list of arrays');
result = _.union([1, 2, 3], [2, 30, 1], [1, 40, [1]]);
equal(result.join(' '), '1 2 3 30 40 1', 'takes the union of a list of nested arrays');
var args = null;
(function(){ args = arguments; })(1, 2, 3);
result = _.union(args, [2, 30, 1], [1, 40]);
equal(result.join(' '), '1 2 3 30 40', 'takes the union of a list of arrays');
result = _.union([1, 2, 3], 4);
deepEqual(result, [1, 2, 3], 'restrict the union to arrays only');
});
test('difference', function() {
var result = _.difference([1, 2, 3], [2, 30, 40]);
equal(result.join(' '), '1 3', 'takes the difference of two arrays');
result = _.difference([1, 2, 3, 4], [2, 30, 40], [1, 11, 111]);
equal(result.join(' '), '3 4', 'takes the difference of three arrays');
result = _.difference([1, 2, 3], 1);
deepEqual(result, [1, 2, 3], 'restrict the difference to arrays only');
});
test('zip', function() {
var names = ['moe', 'larry', 'curly'], ages = [30, 40, 50], leaders = [true];
var stooges = _.zip(names, ages, leaders);
equal(String(stooges), 'moe,30,true,larry,40,,curly,50,', 'zipped together arrays of different lengths');
stooges = _.zip(['moe',30, 'stooge 1'],['larry',40, 'stooge 2'],['curly',50, 'stooge 3']);
deepEqual(stooges, [['moe','larry','curly'],[30,40,50], ['stooge 1', 'stooge 2', 'stooge 3']], 'zipped pairs');
// In the case of difference lengths of the tuples undefineds
// should be used as placeholder
stooges = _.zip(['moe',30],['larry',40],['curly',50, 'extra data']);
deepEqual(stooges, [['moe','larry','curly'],[30,40,50], [undefined, undefined, 'extra data']], 'zipped pairs with empties');
var empty = _.zip([]);
deepEqual(empty, [], 'unzipped empty');
});
test('object', function() {
var result = _.object(['moe', 'larry', 'curly'], [30, 40, 50]);
var shouldBe = {moe: 30, larry: 40, curly: 50};
ok(_.isEqual(result, shouldBe), 'two arrays zipped together into an object');
result = _.object([['one', 1], ['two', 2], ['three', 3]]);
shouldBe = {one: 1, two: 2, three: 3};
ok(_.isEqual(result, shouldBe), 'an array of pairs zipped together into an object');
var stooges = {moe: 30, larry: 40, curly: 50};
ok(_.isEqual(_.object(_.pairs(stooges)), stooges), 'an object converted to pairs and back to an object');
ok(_.isEqual(_.object(null), {}), 'handles nulls');
});
test('indexOf', function() {
var numbers = [1, 2, 3];
numbers.indexOf = null;
equal(_.indexOf(numbers, 2), 1, 'can compute indexOf, even without the native function');
var result = (function(){ return _.indexOf(arguments, 2); })(1, 2, 3);
equal(result, 1, 'works on an arguments object');
equal(_.indexOf(null, 2), -1, 'handles nulls properly');
var num = 35;
numbers = [10, 20, 30, 40, 50];
var index = _.indexOf(numbers, num, true);
equal(index, -1, '35 is not in the list');
numbers = [10, 20, 30, 40, 50]; num = 40;
index = _.indexOf(numbers, num, true);
equal(index, 3, '40 is in the list');
numbers = [1, 40, 40, 40, 40, 40, 40, 40, 50, 60, 70]; num = 40;
index = _.indexOf(numbers, num, true);
equal(index, 1, '40 is in the list');
numbers = [1, 2, 3, 1, 2, 3, 1, 2, 3];
index = _.indexOf(numbers, 2, 5);
equal(index, 7, 'supports the fromIndex argument');
});
test('lastIndexOf', function() {
var numbers = [1, 0, 1];
equal(_.lastIndexOf(numbers, 1), 2);
numbers = [1, 0, 1, 0, 0, 1, 0, 0, 0];
numbers.lastIndexOf = null;
equal(_.lastIndexOf(numbers, 1), 5, 'can compute lastIndexOf, even without the native function');
equal(_.lastIndexOf(numbers, 0), 8, 'lastIndexOf the other element');
var result = (function(){ return _.lastIndexOf(arguments, 1); })(1, 0, 1, 0, 0, 1, 0, 0, 0);
equal(result, 5, 'works on an arguments object');
equal(_.lastIndexOf(null, 2), -1, 'handles nulls properly');
numbers = [1, 2, 3, 1, 2, 3, 1, 2, 3];
var index = _.lastIndexOf(numbers, 2, 2);
equal(index, 1, 'supports the fromIndex argument');
});
test('range', function() {
equal(_.range(0).join(''), '', 'range with 0 as a first argument generates an empty array');
equal(_.range(4).join(' '), '0 1 2 3', 'range with a single positive argument generates an array of elements 0,1,2,...,n-1');
equal(_.range(5, 8).join(' '), '5 6 7', 'range with two arguments a & b, a<b generates an array of elements a,a+1,a+2,...,b-2,b-1');
equal(_.range(8, 5).join(''), '', 'range with two arguments a & b, b<a generates an empty array');
equal(_.range(3, 10, 3).join(' '), '3 6 9', 'range with three arguments a & b & c, c < b-a, a < b generates an array of elements a,a+c,a+2c,...,b - (multiplier of a) < c');
equal(_.range(3, 10, 15).join(''), '3', 'range with three arguments a & b & c, c > b-a, a < b generates an array with a single element, equal to a');
equal(_.range(12, 7, -2).join(' '), '12 10 8', 'range with three arguments a & b & c, a > b, c < 0 generates an array of elements a,a-c,a-2c and ends with the number not less than b');
equal(_.range(0, -10, -1).join(' '), '0 -1 -2 -3 -4 -5 -6 -7 -8 -9', 'final example in the Python docs');
});
})();