es6 compile errors with no location information

[arolson101]

I'm trying to switch over to the latest typescript so that I can use async/await inside a mocha test. My tsconfig specifies es6 and module commonjs. If I run tsc from the command-line it reports no errors, but when I run from gulp (which registers ts-node) I get this error.

[15:15:17] Using gulpfile C:\updraft\Gulpfile.js
[15:15:17] Starting 'test'...
[15:15:20] 'test' errored after 3.03 s
[15:15:20] SyntaxError in plugin 'gulp-mocha'
Message:
    Block-scoped declarations (let, const, function, class) not yet supported outside strict mode Stack:
SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:413:25)
    at Object.loader (C:\updraft\node_modules\ts-node\dist\ts-node.js:102:18)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (C:\updraft\src\index.ts:1:20)
    at Module._compile (module.js:434:26)
    at Object.loader (C:\updraft\node_modules\ts-node\dist\ts-node.js:102:18)

So problem (1) is that there shouldn't be a difference between tsc and ts-node (I have typescript@next installed locally and globally), and (2) is that the output gives no indication of where (file/line) the error was found

[blakeembrey]

You need to use gulpfile.ts. It's using gulpfile.js above.

Edit: Make sure you don't have both - .js will resolve before .ts.
Edit 2: That error is also from node, not from TypeScript or ts-node.

[arolson101]

I set up a gulpfile.js to load my renamed gulpfile.ts using the instructions here (substituting typescript-register with ts-node/register) but the error remains the same.

Is there a guide for how to use ts-node with gulp?

[blakeembrey]

No guide. You just create a gulpfile.ts and have ts-node installed. It works automatically. Do you have a project you can share with this? Do you have a tsconfig.json file at all?

[arolson101]

yep, that worked. All is good. You should put a note about using Gulpfile.ts in your readme.md

[arolson101]

I spoke too soon; I had forgotten to redo the es6/await changes in my test. I'm still getting

[19:16:38] Requiring external module ts-node/register
[19:16:45] Using gulpfile ~/Developer/updraft/Gulpfile.ts
[19:16:45] Starting 'test'...
[19:16:48] 'test' errored after 2.63 s
[19:16:48] SyntaxError in plugin 'gulp-mocha'
Message:
    Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
Stack:
SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:413:25)
    at Object.loader (/Users/aolson/Developer/updraft/node_modules/ts-node/dist/ts-node.js:102:18)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (/Users/aolson/Developer/updraft/src/index.ts:1:20)
    at Module._compile (module.js:434:26)
    at Object.loader (/Users/aolson/Developer/updraft/node_modules/ts-node/dist/ts-node.js:102:18)

[arolson101]

I do have a tsconfig.json
I've published my changes here: https://github.com/arolson101/updraft/tree/changelog

[blakeembrey]

@arolson101 You're compiling to ES6. Set it to es5 (https://github.com/arolson101/updraft/blob/changelog/tsconfig.json#L4).

[blakeembrey]

But that won't work because you're using [edit: certain] ES6 features, so what you should do is what the directions say. 'use strict' in your file.

[arolson101]

But which file? And why does it compile fine under tsc but not ts-node?

-ARO

On Nov 2, 2015, at 7:29 PM, Blake Embrey [email protected] wrote:

But that won't work because you're using ES6 features, so what you should do is what the directions say. 'use strict' in your file.

—
Reply to this email directly or view it on GitHub.

[blakeembrey]

It does compile using ts-node. As I've said, that's an error from node.

Edit: ts-node does not output any SyntaxErrors, those are JS issues. This module formats the errors with line/numbers like in the README.

[blakeembrey]

The issue is you're compiling to ES6 in tsconfig.json (which ts-node uses) and node does not support the ES6 output yet - hence "block-scoped declarations (let, const, function, class) not yet supported outside strict mode".

[arolson101]

Ahhhh. Ok then. Thanks for the help!

[blakeembrey]

No worries, I'll add some docs on node/gulp/typescript interop when I have a chance - just made an issue to track that. You should be able to use multiple tsconfig.json files too, or move tsconfig.json away from the CWD to avoid it loading automatically (neither are great fixes, but that's an issue when we have a lot of tools consuming the same file).

[arolson101]

Looking around the web, it seems that normally nodejs would report the line that has the problem; this is what ts-node is not doing. For example:

http.createServer(app).listen(app.get('port'), function(){
^^^^
SyntaxError: Unexpected identifier
    at Module._compile (module.js:439:25)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)
    at node.js:929:3

ts-node is missing the line & error indicators. For instance:

[21:58:17] SyntaxError in plugin 'gulp-mocha'
Message:
    Unexpected identifier
Stack:
SyntaxError: Unexpected identifier
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:413:25)
    at Object.loader (/Users/aolson/Developer/updraft/node_modules/ts-node/dist/ts-node.js:103:18)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at /Users/aolson/Developer/updraft/node_modules/mocha/lib/mocha.js:216:27
    at Array.forEach (native)
    at Mocha.loadFiles (/Users/aolson/Developer/updraft/node_modules/mocha/lib/mocha.js:213:14)