continuation.js missing from dist/commonjs/runtime in Traceur 0.0.110

[stuartZhang]

I upgrade the Google Traceur to the latest 0.0.110. However, the compilation-output ES5 JavaScript program can't work in the web browser.

1. The transpiling command for Traceur:

node_modules/.bin/traceur
--script=www/js/widget-nest-thermostat.bbjs
--out=www/js/widget-nest-thermostat.js
--require=true
--arrow-functions=true --block-binding=true --classes=true
--computed-property-names=true --default-parameters=true
--destructuring=true --for-of=true --generators=true --numeric-literals=true
--property-methods=true --property-name-shorthand=true --rest-parameters=true
--spread=true --symbols=true --template-literals=true --unicode-escape-sequences=true
--unicode-expressions=true --proper-tail-calls=true --annotations=true
--array-comprehension=true --async-functions=true --async-generators=true
--exponentiation=true --export-from-extended=true --for-on=true
--generator-comprehension=true --member-variables=true --spread-properties=true
--types=true --experimental --source-maps=file

2. The traceur runtime has been introduced in the HTML page.

<script type="text/javascript" src="/js/traceur-runtime.js"></script>

The file "traceur-runtime.js" is copied from the folder "node_modules/traceur/bin".

3. The Error is thrown from the web browser, when I visit the web page.

  **TypeError: Cannot read property 'default' of undefined**

By scanning the compilatio-output ES5 JS program, I discovered the error point is

var $__initTailRecursiveFunction = $traceurRuntime.getModule($traceurRuntime.normalizeModuleName("traceur/dist/commonjs/runtime/modules/initTailRecursiveFunction.js", "widget-nest-thermostat.bbjs")).default;

That's to say, $traceurRuntime.getModule($traceurRuntime.normalizeModuleName("traceur/dist/commonjs/runtime/modules/initTailRecursiveFunction.js", "widget-nest-thermostat.bbjs")) returns null.

Memo: in my project, ES6 JS file is suffixed with ".bbjs". After they are compiled, their corresponding ES5 file is ".js".

[stuartZhang]

It's worth saying that, as for the traceur@0.0.107, the compilation-output ES5 JavaScript program works in the web browser.

Is it a regression bug for the version 0.0.110?

[johnjbarton]

Please look in to your output for the $traceurRuntime.registerModule() with the name from your initTailRecursiveFunction.js. Also compare these with the the old and new versions of the compiler.

The compiler generates $traceurRuntime.registerModule() to store the modules and $traceurRuntime.getModule() to retrieve them. The register call must be missing or out of order.

Once you have a hint perhaps you can create a small test case. We did make some changes in the runtime.

[stuartZhang]

Given my investigation, the Traceur@0.0.110-compilation ES5 code is very different from Traceur@0.0.107.

The below JS statement is inexistent in the Traceur@0.0.107 compilation result.
var $__continuation = $traceurRuntime.getModule($traceurRuntime.normalizeModuleName("traceur/dist/commonjs/runtime/modules/continuation.js", "widget-nest-thermostat.bbjs")).default;

On the contrary, in Traceur@0.0.110 compilation result, the above statement is in the 2nd line.

However, in the web browser, the above JS statement brings about a NullPointer error, because $traceurRuntime.getModule($traceurRuntime.normalizeModuleName("traceur/dist/commonjs/runtime/modules/continuation.js", "widget-nest-thermostat.bbjs")) return null.

The following picture shows the differences between Traceur@0.0.110 and Traceur@0.0.107 compilation results.

[johnjbarton]

Looks like continuation.js did not make it into the commonjs runtime.

[arv]

I see dist/commonjs/runtime/modules/continuation.js in the npm release.

I suspect there is cyclic dependency with the require that causes this to be undefined. I'll try to create a minimal test case.

For now you can turn off import-runtime or turn off proper-tail-calls to get you unblocked.

[richgilbank]

Hey folks, thanks for the continued work on the project! 💃
Just wanted to leave a note here for anyone else currently experiencing issues with this - turning off properTailCalls didn't seem to do the trick for me, but turning off importRuntime did. ¯\(ツ)/¯
ref: richgilbank/Scratch-JS@d0f2e7b#diff-402dfb8c015ea27de73101a0b8d9fc32R17

[stuartZhang]

Cloud you please teach me what the feature "importRuntime" takes on during the transformation from ES 6 to ES 5?