initial draft of removing sparse array workarounds. · jashkenas/underscore@4e4bc19

var ifnull = _.map(null, function(){});

ok(_.isArray(ifnull) && ifnull.length === 0, 'handles a null properly');

var length = _.map(Array(2), function(v) { return v; }).length;

equal(length, 2, "can preserve a sparse array's length");

});

test('collections: reduce', function() {

ok(_.reduce(null, function(){}, 138) === 138, 'handles a null (with initial value) properly');

equal(_.reduce([], function(){}, undefined), undefined, 'undefined can be passed as a special case');

raises(function() { _.reduce([], function(){}); }, TypeError, 'throws an error for empty arrays with no initial value');

var sparseArray = [];

sparseArray[0] = 20;

sparseArray[2] = -5;

equal(_.reduce(sparseArray, function(a, b){ return a - b; }), 25, 'initially-sparse arrays with no memo');

});

test('collections: reduceRight', function() {

equal(_.reduceRight([], function(){}, undefined), undefined, 'undefined can be passed as a special case');

raises(function() { _.reduceRight([], function(){}); }, TypeError, 'throws an error for empty arrays with no initial value');

var sparseArray = [];

sparseArray[0] = 20;

sparseArray[2] = -5;

equal(_.reduceRight(sparseArray, function(a, b){ return a - b; }), -25, 'initially-sparse arrays with no memo');

});

test('collections: detect', function() {