diff options
-rw-r--r-- | app/scripts/lib/nodeify.js | 15 | ||||
-rw-r--r-- | test/unit/app/nodeify-test.js | 49 |
2 files changed, 57 insertions, 7 deletions
diff --git a/app/scripts/lib/nodeify.js b/app/scripts/lib/nodeify.js index 25be6537b..a813ae679 100644 --- a/app/scripts/lib/nodeify.js +++ b/app/scripts/lib/nodeify.js @@ -1,5 +1,5 @@ const promiseToCallback = require('promise-to-callback') -const noop = function () {} +const callbackNoop = function (err) { if (err) throw err } /** * A generator that returns a function which, when passed a promise, can treat that promise as a node style callback. @@ -11,6 +11,7 @@ const noop = function () {} */ module.exports = function nodeify (fn, context) { return function () { + // parse arguments const args = [].slice.call(arguments) const lastArg = args[args.length - 1] const lastArgIsCallback = typeof lastArg === 'function' @@ -19,8 +20,16 @@ module.exports = function nodeify (fn, context) { callback = lastArg args.pop() } else { - callback = noop + callback = callbackNoop } - promiseToCallback(fn.apply(context, args))(callback) + // call the provided function and ensure result is a promise + let result + try { + result = Promise.resolve(fn.apply(context, args)) + } catch (err) { + result = Promise.reject(err) + } + // wire up promise resolution to callback + promiseToCallback(result)(callback) } } diff --git a/test/unit/app/nodeify-test.js b/test/unit/app/nodeify-test.js index 938b76c68..0dafc6653 100644 --- a/test/unit/app/nodeify-test.js +++ b/test/unit/app/nodeify-test.js @@ -2,16 +2,16 @@ const assert = require('assert') const nodeify = require('../../../app/scripts/lib/nodeify') describe('nodeify', function () { - var obj = { + const obj = { foo: 'bar', promiseFunc: function (a) { - var solution = this.foo + a + const solution = this.foo + a return Promise.resolve(solution) }, } it('should retain original context', function (done) { - var nodified = nodeify(obj.promiseFunc, obj) + const nodified = nodeify(obj.promiseFunc, obj) nodified('baz', function (err, res) { if (!err) { assert.equal(res, 'barbaz') @@ -22,7 +22,7 @@ describe('nodeify', function () { }) }) - it('should allow the last argument to not be a function', function (done) { + it('no callback - should allow the last argument to not be a function', function (done) { const nodified = nodeify(obj.promiseFunc, obj) try { nodified('baz') @@ -31,4 +31,45 @@ describe('nodeify', function () { done(new Error('should not have thrown if the last argument is not a function')) } }) + + it('no callback - should asyncly throw an error if underlying function does', function (done) { + const nodified = nodeify(async () => { throw new Error('boom!') }, obj) + process.prependOnceListener('uncaughtException', function (err) { + assert.ok(err, 'got expected error') + assert.ok(err.message.includes('boom!'), 'got expected error message') + done() + }) + try { + nodified('baz') + } catch (err) { + done(new Error('should not have thrown an error synchronously')) + } + }) + + it('sync functions - returns value', function (done) { + const nodified = nodeify(() => 42) + try { + nodified((err, result) => { + if (err) return done(new Error(`should not have thrown any error: ${err.message}`)) + assert.equal(42, result, 'got expected result') + }) + done() + } catch (err) { + done(new Error(`should not have thrown any error: ${err.message}`)) + } + }) + + it('sync functions - handles errors', function (done) { + const nodified = nodeify(() => { throw new Error('boom!') }) + try { + nodified((err, result) => { + if (result) return done(new Error('should not have returned any result')) + assert.ok(err, 'got expected error') + assert.ok(err.message.includes('boom!'), 'got expected error message') + }) + done() + } catch (err) { + done(new Error(`should not have thrown any error: ${err.message}`)) + } + }) }) |