54 lines
1.6 KiB
JavaScript
54 lines
1.6 KiB
JavaScript
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var lazyIterators = require("../lib/lazy-iterators");
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exports.convertingArrayToIteratorAndBack = function(test) {
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var original = ["apple", "banana", "coconut"];
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var iterator = lazyIterators.fromArray(original);
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var reconstituted = iterator.toArray();
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test.deepEqual(original, reconstituted);
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test.done();
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};
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exports.mapAppliesFunctionToEveryElement = function(test) {
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var original = [1, 2, 3];
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var squared = lazyIterators.fromArray(original).map(function(i) {
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return i * i;
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}).toArray();
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test.deepEqual([1, 4, 9], squared);
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test.done();
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};
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exports.mappingFunctionIsOnlyCalledWhenNecessary = function(test) {
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var original = [1, 2, 3];
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var faultySquared = lazyIterators.fromArray(original).map(function(i) {
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if (i === 1) {
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return i;
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} else {
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throw new Error("Can only calculate the square of one");
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}
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}).first();
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test.deepEqual(1, faultySquared);
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test.done();
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};
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exports.filterRetainsElementsThatSatisfyPredicate = function(test) {
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var original = [1, 2, 3, 4];
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var even = lazyIterators.fromArray(original).filter(function(i) {
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return i % 2 === 0;
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}).toArray();
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test.deepEqual([2, 4], even);
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test.done();
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};
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exports.firstReturnsFirstElementOfArray = function(test) {
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var original = [1, 2, 3, 4];
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var first = lazyIterators.fromArray(original).first();
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test.deepEqual(1, first);
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test.done();
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};
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exports.firstIsNullIfArrayIsEmpty = function(test) {
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var first = lazyIterators.fromArray([]).first();
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test.same(null, first);
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test.done();
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};
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