lodash/vendor/underscore/test/arrays.js

(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()"');
    deepEqual(_.first([1, 2, 3], 0), [], 'can pass an index to first');
    deepEqual(_.first([1, 2, 3], 2), [1, 2], 'can pass an index to first');
    deepEqual(_.first([1, 2, 3], 5), [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);
    deepEqual(result, [1, 1], 'works well with _.map');
    result = (function() { return _.first([1, 2, 3], 2); }());
    deepEqual(result, [1, 2]);

    equal(_.first(null), undefined, 'handles nulls');
    strictEqual(_.first([1, 2, 3], -1).length, 0);
  });

  test('head', function() {
    strictEqual(_.first, _.head, 'alias for first');
  });

  test('take', function() {
    strictEqual(_.first, _.take, 'alias for first');
  });

  test('rest', function() {
    var numbers = [1, 2, 3, 4];
    deepEqual(_.rest(numbers), [2, 3, 4], 'working rest()');
    deepEqual(_.rest(numbers, 0), [1, 2, 3, 4], 'working rest(0)');
    deepEqual(_.rest(numbers, 2), [3, 4], 'rest can take an index');
    var result = (function(){ return _(arguments).rest(); }(1, 2, 3, 4));
    deepEqual(result, [2, 3, 4], 'works on arguments object');
    result = _.map([[1, 2, 3], [1, 2, 3]], _.rest);
    deepEqual(_.flatten(result), [2, 3, 2, 3], 'works well with _.map');
    result = (function(){ return _(arguments).rest(); }(1, 2, 3, 4));
    deepEqual(result, [2, 3, 4], 'works on arguments object');
  });

  test('tail', function() {
    strictEqual(_.rest, _.tail, 'alias for rest');
  });

  test('drop', function() {
    strictEqual(_.rest, _.drop, 'alias for rest');
  });

  test('initial', function() {
    deepEqual(_.initial([1, 2, 3, 4, 5]), [1, 2, 3, 4], 'working initial()');
    deepEqual(_.initial([1, 2, 3, 4], 2), [1, 2], 'initial can take an index');
    deepEqual(_.initial([1, 2, 3, 4], 6), [], 'initial can take a large index');
    var result = (function(){ return _(arguments).initial(); }(1, 2, 3, 4));
    deepEqual(result, [1, 2, 3], 'initial works on arguments object');
    result = _.map([[1, 2, 3], [1, 2, 3]], _.initial);
    deepEqual(_.flatten(result), [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');
    deepEqual(_.last([1, 2, 3], 0), [], 'can pass an index to last');
    deepEqual(_.last([1, 2, 3], 2), [2, 3], 'can pass an index to last');
    deepEqual(_.last([1, 2, 3], 5), [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);
    deepEqual(result, [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];
    deepEqual(_.without(list, 0, 1), [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));
    deepEqual(result, [2, 3, 4], 'works on an arguments object');

    list = [{one : 1}, {two : 2}];
    equal(_.without(list, {one : 1}).length, 2, 'uses real object identity for comparisons.');
    equal(_.without(list, list[0]).length, 1, 'ditto.');
  });

  test('uniq', function() {
    var list = [1, 2, 1, 3, 1, 4];
    deepEqual(_.uniq(list), [1, 2, 3, 4], 'can find the unique values of an unsorted array');

    list = [1, 1, 1, 2, 2, 3];
    deepEqual(_.uniq(list, true), [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; };
    deepEqual(_.map(_.uniq(list, false, iterator), iterator), ['moe', 'curly', 'larry'], 'can find the unique values of an array using a custom iterator');

    deepEqual(_.map(_.uniq(list, iterator), iterator), ['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];
    deepEqual(_.uniq(list, true, iterator), [1, 2, 3, 4], 'iterator works with sorted array');

    var result = (function(){ return _.uniq(arguments); }(1, 2, 1, 3, 1, 4));
    deepEqual(result, [1, 2, 3, 4], 'works on an arguments object');

    var a = {}, b = {}, c = {};
    deepEqual(_.uniq([a, b, a, b, c]), [a, b, c], 'works on values that can be tested for equivalency but not ordered');

    deepEqual(_.uniq(null), []);

    var context = {};
    list = [3];
    _.uniq(list, function(value, index, array) {
      strictEqual(this, context);
      strictEqual(value, 3);
      strictEqual(index, 0);
      strictEqual(array, list);
    }, context);

    deepEqual(_.uniq([{a: 1, b: 1}, {a: 1, b: 2}, {a: 1, b: 3}, {a: 2, b: 1}], 'a'), [{a: 1, b: 1}, {a: 2, b: 1}], 'can use pluck like iterator');
    deepEqual(_.uniq([{0: 1, b: 1}, {0: 1, b: 2}, {0: 1, b: 3}, {0: 2, b: 1}], 0), [{0: 1, b: 1}, {0: 2, b: 1}], 'can use falsey pluck like iterator');
  });

  test('unique', function() {
    strictEqual(_.uniq, _.unique, 'alias for uniq');
  });

  test('intersection', function() {
    var stooges = ['moe', 'curly', 'larry'], leaders = ['moe', 'groucho'];
    deepEqual(_.intersection(stooges, leaders), ['moe'], 'can take the set intersection of two arrays');
    deepEqual(_(stooges).intersection(leaders), ['moe'], 'can perform an OO-style intersection');
    var result = (function(){ return _.intersection(arguments, leaders); }('moe', 'curly', 'larry'));
    deepEqual(result, ['moe'], 'works on an arguments object');
    var theSixStooges = ['moe', 'moe', 'curly', 'curly', 'larry', 'larry'];
    deepEqual(_.intersection(theSixStooges, leaders), ['moe'], 'returns a duplicate-free array');
    result = _.intersection([2, 4, 3, 1], [1, 2, 3]);
    deepEqual(result, [2, 3, 1], 'preserves order of first array');
    result = _.intersection(null, [1, 2, 3]);
    equal(Object.prototype.toString.call(result), '[object Array]', 'returns an empty array when passed null as first argument');
    equal(result.length, 0, 'returns an empty array when passed null as first argument');
    result = _.intersection([1, 2, 3], null);
    equal(Object.prototype.toString.call(result), '[object Array]', 'returns an empty array when passed null as argument beyond the first');
    equal(result.length, 0, 'returns an empty array when passed null as argument beyond the first');
  });

  test('union', function() {
    var result = _.union([1, 2, 3], [2, 30, 1], [1, 40]);
    deepEqual(result, [1, 2, 3, 30, 40], 'takes the union of a list of arrays');

    result = _.union([1, 2, 3], [2, 30, 1], [1, 40, [1]]);
    deepEqual(result, [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]);
    deepEqual(result, [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]);
    deepEqual(result, [1, 3], 'takes the difference of two arrays');

    result = _.difference([1, 2, 3, 4], [2, 30, 40], [1, 11, 111]);
    deepEqual(result, [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];
    deepEqual(_.zip(names, ages, leaders), [
      ['moe', 30, true],
      ['larry', 40, undefined],
      ['curly', 50, undefined]
    ], 'zipped together arrays of different lengths');

    var 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');

    deepEqual(_.zip(null), [], 'handles null');
    deepEqual(_.zip(), [], '_.zip() returns []');
  });

  test('object', function() {
    var result = _.object(['moe', 'larry', 'curly'], [30, 40, 50]);
    var shouldBe = {moe: 30, larry: 40, curly: 50};
    deepEqual(result, shouldBe, 'two arrays zipped together into an object');

    result = _.object([['one', 1], ['two', 2], ['three', 3]]);
    shouldBe = {one: 1, two: 2, three: 3};
    deepEqual(result, shouldBe, 'an array of pairs zipped together into an object');

    var stooges = {moe: 30, larry: 40, curly: 50};
    deepEqual(_.object(_.pairs(stooges)), stooges, 'an object converted to pairs and back to an object');

    deepEqual(_.object(null), {}, 'handles nulls');
  });

  test('indexOf', function() {
    var numbers = [1, 2, 3];
    equal(_.indexOf(numbers, 2), 1, 'can compute indexOf');
    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;
    equal(_.indexOf(numbers, num, true), 1, '40 is in the list');
    equal(_.indexOf(numbers, 6, true), -1, '6 isnt in the list');
    equal(_.indexOf([1, 2, 5, 4, 6, 7], 5, true), -1, 'sorted indexOf doesn\'t uses binary search');
    ok(_.every(['1', [], {}, null], function() {
      return _.indexOf(numbers, num, {}) === 1;
    }), 'non-nums as fromIndex make indexOf assume sorted');

    numbers = [1, 2, 3, 1, 2, 3, 1, 2, 3];
    index = _.indexOf(numbers, 2, 5);
    equal(index, 7, 'supports the fromIndex argument');

    index = _.indexOf([,,,], undefined);
    equal(index, 0, 'treats sparse arrays as if they were dense');

    var array = [1, 2, 3, 1, 2, 3];
    strictEqual(_.indexOf(array, 1, -3), 3, 'neg `fromIndex` starts at the right index');
    strictEqual(_.indexOf(array, 1, -2), -1, 'neg `fromIndex` starts at the right index');
    strictEqual(_.indexOf(array, 2, -3), 4);
    _.each([-6, -8, -Infinity], function(fromIndex) {
      strictEqual(_.indexOf(array, 1, fromIndex), 0);
    });
    strictEqual(_.indexOf([1, 2, 3], 1, true), 0);
  });

  test('lastIndexOf', function() {
    var numbers = [1, 0, 1];
    var falsey = [void 0, '', 0, false, NaN, null, undefined];
    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');

    var array = [1, 2, 3, 1, 2, 3];

    strictEqual(_.lastIndexOf(array, 1, 0), 0, 'starts at the correct from idx');
    strictEqual(_.lastIndexOf(array, 3), 5, 'should return the index of the last matched value');
    strictEqual(_.lastIndexOf(array, 4), -1, 'should return `-1` for an unmatched value');

    strictEqual(_.lastIndexOf(array, 1, 2), 0, 'should work with a positive `fromIndex`');

    _.each([6, 8, Math.pow(2, 32), Infinity], function(fromIndex) {
      strictEqual(_.lastIndexOf(array, undefined, fromIndex), -1);
      strictEqual(_.lastIndexOf(array, 1, fromIndex), 3);
      strictEqual(_.lastIndexOf(array, '', fromIndex), -1);
    });

    var expected = _.map(falsey, function(value) {
      return typeof value == 'number' ? -1 : 5;
    });

    var actual = _.map(falsey, function(fromIndex) {
      return _.lastIndexOf(array, 3, fromIndex);
    });

    deepEqual(actual, expected, 'should treat falsey `fromIndex` values, except `0` and `NaN`, as `array.length`');
    strictEqual(_.lastIndexOf(array, 3, '1'), 5, 'should treat non-number `fromIndex` values as `array.length`');
    strictEqual(_.lastIndexOf(array, 3, true), 5, 'should treat non-number `fromIndex` values as `array.length`');

    strictEqual(_.lastIndexOf(array, 2, -3), 1, 'should work with a negative `fromIndex`');
    strictEqual(_.lastIndexOf(array, 1, -3), 3, 'neg `fromIndex` starts at the right index');

    deepEqual(_.map([-6, -8, -Infinity], function(fromIndex) {
      return _.lastIndexOf(array, 1, fromIndex);
    }), [0, -1, -1]);
  });

  test('range', function() {
    deepEqual(_.range(0), [], 'range with 0 as a first argument generates an empty array');
    deepEqual(_.range(4), [0, 1, 2, 3], 'range with a single positive argument generates an array of elements 0,1,2,...,n-1');
    deepEqual(_.range(5, 8), [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');
    deepEqual(_.range(8, 5), [], 'range with two arguments a & b, b<a generates an empty array');
    deepEqual(_.range(3, 10, 3), [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');
    deepEqual(_.range(3, 10, 15), [3], 'range with three arguments a & b & c, c > b-a, a < b generates an array with a single element, equal to a');
    deepEqual(_.range(12, 7, -2), [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');
    deepEqual(_.range(0, -10, -1), [0, -1, -2, -3, -4, -5, -6, -7, -8, -9], 'final example in the Python docs');
  });

}());