bug: 0.16.23, Inconsistent loading using import

[unional]

I have a ts package importing domready:
import * as domready from 'domready';

It works fine inside the package. domready is resolved to the function.

When I reference this package, it fails. domready is resolved to { default: Function }.

Tried to trace the issue, seems like one is called by linkDynamicModule() L3109 (working)
and the other is called by link() L2838 (not working).

[frankwallis]

It looks correct to me that import * as domready from 'domready'; should return { default: Function }. You should use import domready from 'domready'; to get the default export. If TypeScript is not picking up on this then you may have an incorrect 'domready' declaration?

[unional]

I originally was doing import domready from 'domready', but then in the latest build it failed as it returned undefined. In either case, the behavior should be consistent.

However, after I tried to roll back to 0.16.20 and test things out, it starts to work again.

Will continue to monitor a bit. Will close this issue now and reopen it if needed.

[unional]

Oh, by the way domready was not doing export default, so it may be __ESModule related?

[frankwallis]

Yes I do agree there is an issue, but it is hard to pinpoint. It seems that though files are not reliably being detected as commonjs/esm.

This issue is also similar: alexisvincent/systemjs-hot-reloader#42

[unional]

I am able to reproduce the issue.

It turns out to be related to the module flag.
In config.js:

System.config({
  ...
  typescriptOptions: {
    module: "system"
    ...
  }
  ...

module	import domready from `domready'	import * as dr from 'domready'
system	works	fails
commonjs	fails	works
amd	fails	works
umd	fails	works

The error come back is (note I'm using karma-chrome, so the non-error message is not related to karma-phantomjs ariya/phantomjs#12381):

Chrome 47.0.2526 (Windows 8.1 0.0.0) WARN: '%cWarning: a promise was rejected with a non-error: [object String]
    at linkSetFailed (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:675:13)
    at http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:571:9
    at doDynamicExecute (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:719:7)
    at link (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:912:20)
    at doLink (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:570:7)
    at updateLinkSetOnLoad (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:618:18)
    at http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:430:11

From previous event:
    at createLinkSet (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:516:20)
    at http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:483:21
From previous event:
    at loadModule (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:259:12)
    at http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:800:11
From previous event:
    at SystemJSLoader.Loader.import (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:791:8)
    at SystemJSLoader.import (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:1661:25)
    at http://localhost:9877/base/node_modules/karma-jspm/src/adapter.js?5817daa21dc8df52825dd23824c41a6dfb0a7240:55:44
    at tryCatchReject (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:1257:30)
    at runContinuation1 (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:1216:4)
    at Fulfilled.when (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:1004:4)
    at Pending.run (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:895:13)
    at Scheduler._drain (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:171:19)
    at Scheduler.drain (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:136:9)
    at MutationObserver.run (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:342:4)', 'color: darkorange'
Chrome 47.0.2526 (Windows 8.1 0.0.0) WARN: '%cWarning: a promise was rejected with a non-error: [object String]
    at createImportPromise (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:736:43)
    at http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:799:47
From previous event:
    at SystemJSLoader.Loader.import (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:791:8)
    at SystemJSLoader.import (http://localhost:9877/base/jspm_packages/system.src.js?60ced582fc3750b88f77044342c775e5c3c18d0d:1661:25)
    at http://localhost:9877/base/node_modules/karma-jspm/src/adapter.js?5817daa21dc8df52825dd23824c41a6dfb0a7240:55:44
    at tryCatchReject (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:1257:30)
    at runContinuation1 (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:1216:4)
    at Fulfilled.when (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:1004:4)
    at Pending.run (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:895:13)
    at Scheduler._drain (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:171:19)
    at Scheduler.drain (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:136:9)
    at MutationObserver.run (http://localhost:9877/base/jspm_packages/system-polyfills.src.js?be0f4ba76d282ea43052da5d0d22a53cea9237ca:342:4)', 'color: darkorange'
Chrome 47.0.2526 (Windows 8.1 0.0.0) ERROR: 'Potentially unhandled rejection [2] Uncaught Uncaught Uncaught TypeError: expecting a function but got [object Undefined]
        Evaluating http://localhost:9877/base/src/bootstrapper.ts
        Evaluating http://localhost:9877/base/src/index.ts
        Evaluating http://localhost:9877/base/spec/bootstrapper.spec.ts
        Error loading http://localhost:9877/base/spec/bootstrapper.spec.ts (WARNING: non-Error used)'

[frederikschubert]

I see the same behavior with momentjs. The typings suggest to import it as a module with import * as moment from "moment"; but this only worked with commonjs module format.
After switching it to system format as the new version of plugin-typescript suggested I have to import moment as the default export import moment from "moment".

[frankwallis]

I think this may be related to this issue. There is a new compiler option in 1.8.0 --allowSyntheticDefaultImports which could solve it, see here.

[unional]

Importing bluebird and domready, where bluebird is "format global" and domready is"format cjs"`.

Correction: I forgot that import B from 'bluebird' and import * as B from 'bluebird' suppose to do two different things.

import * as B from 'bluebird' returns the module export while import B from 'bluebird' returns the default export.

In simplest way, import B from 'bluebird' returns a Promise that you can call with new B(...), while import * as B from 'bluebird' returns a module object and you need new B.default() to access the promise function.

In this sense, commonjs/amd/umd + import * as dr form 'domready' should not returns the domready() function, which it currently does.

Updating the table:

module	import dr from `domready'	import * as dr from 'domready'	import B from 'bluebird'	import * as B from 'bluebird'
system	dr()	{ default() }	B()	{ default() }
commonjs/amd/umd	undefined	dr()	undefined	B()
tsd	N	Y	N	Y

To technically module: "system" is doing the right thing while others are not.
I understand the other issue var m = require('some-es6-module').default, but it seems like the transition to import is still not settled?

[unional]

Adding references
microsoft/TypeScript#2839
microsoft/TypeScript#4668

[unional]

Close as it is a duplicate of microsoft/TypeScript#5285