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Promise.inSequence
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| <title>Promise.inSequence</title> | |
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| function forEachinSequence(actions) { | |
| var last = Promise.resolve(); | |
| actions.forEach(function (next) { | |
| last = last.then(function () { | |
| return next(); | |
| }); | |
| }); | |
| return last; | |
| } | |
| function inSequence(actions) { | |
| var last = Promise.resolve(); | |
| var results = []; | |
| actions.forEach(function (next) { | |
| last = last.then(function () { | |
| return next(); | |
| }) | |
| .then(function (result) { | |
| results.push(result); | |
| }); | |
| }); | |
| return last.then(function () { | |
| return results; | |
| }); | |
| } | |
| function recursiveInSequence(actions, results) { | |
| results = results || []; | |
| var action = actions[0]; | |
| return action() | |
| .then(function (result) { | |
| results.push(result); | |
| if (actions.length === 1) { | |
| return results; | |
| } else { | |
| return recursiveInSequence(actions.slice(1), results); | |
| } | |
| }); | |
| } | |
| function reduceInSequence(actions) { | |
| return actions.reduce(function (last, action) { | |
| return last.then(function (results) { | |
| return action() | |
| .then(function (result) { | |
| results.push(result); | |
| return results; | |
| }); | |
| }); | |
| }, Promise.resolve([])); | |
| } | |
| describe('Promise.inSequence', function () { | |
| function action(delay, seq) { | |
| return function () { | |
| var result = "delay-" + delay; | |
| return new Promise(function (resolve) { | |
| if (seq) { | |
| seq.push(result); | |
| } | |
| resolve(result); | |
| }, delay); | |
| } | |
| } | |
| function test(inseq, name, withResults) { | |
| describe(name, function () { | |
| it("should work with an array of 2 actions", function (done) { | |
| var seq = []; | |
| inseq([action(50, seq), action(10, seq)]) | |
| .then(function () { | |
| expect(seq).toEqual(["delay-50", "delay-10"]); | |
| done(); | |
| }); | |
| }); | |
| it("should work with an array of more than 2 actions", function (done) { | |
| var seq = []; | |
| inseq([ | |
| action(50, seq), | |
| action(10, seq), | |
| action(11, seq), | |
| action(5, seq)]) | |
| .then(function () { | |
| expect(seq).toEqual([ | |
| "delay-50", | |
| "delay-10", | |
| "delay-11", | |
| "delay-5", | |
| ]); | |
| done(); | |
| }); | |
| }); | |
| if (withResults) { | |
| it("should resolve to an array with all the results", function (done) { | |
| inseq([ | |
| action(1), | |
| action(2), | |
| action(3) | |
| ]).then(function (results) { | |
| expect(results).toEqual([ | |
| "delay-1", | |
| "delay-2", | |
| "delay-3" | |
| ]); | |
| done(); | |
| }); | |
| }); | |
| } | |
| }); | |
| } | |
| test(forEachinSequence, "forEachinSequence (ignoring results)"); | |
| test(inSequence, "inSequence", true); | |
| test(recursiveInSequence, "recursiveInSequence", true); | |
| test(reduceInSequence, "reduceInSequence", true); | |
| }); |
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