When I have an error in my es6 code which leads to an error of the traceur transpiling process the gulp watch will be exited too...

Is there a way to prevent this...

Where this page: https://www.npmjs.org/package/gulp-traceur

has this line: .pipe(traceur({sourceMap: true})) ,

it needs to instead be: .pipe(traceur({"sourceMaps": true}))

Suggestion: Include the same on the github README, because most everyone will need source maps for dev-time.

When using the CLI interface from tracuer it does this:
https://github.com/google/traceur-compiler/blob/master/src/node/compile-single-file.js#L36-L38

The public api is a little different https://github.com/google/traceur-compiler/blob/master/src/node/api.js#L71

I have not tried this on node but it causes big problems if your trying to use this module to build files for the browser (my use case)... This could be a bug in the public tracuer API (or maybe its just for node)... Filing the issue here mostly so I can come back and fix it in the morning.

Back in the version 0.13.0 there was only one sourceMappingURL at the end of the files.

Contents of the test should generate source maps with the [email protected]

"use strict";
[].map((function(v) {
  return v + 1;
}));

//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImZpeHR1cmUuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IkFBQUE7QUFBQSxDQUFDLElBQUksQUFBQyxFQUFDLFNBQUEsQ0FBQTtPQUFLLENBQUEsQ0FBQSxFQUFJLEVBQUE7QUFBQSxFQUFDLENBQUE7QUFBQSIsImZpbGUiOiJmaXh0dXJlLmpzIiwic291cmNlc0NvbnRlbnQiOlsiW10ubWFwKHYgPT4gdiArIDEpIl0sInNvdXJjZVJvb3QiOiIvc291cmNlLyJ9

Is it normal to have two of them in the new version 0.14.0 ?

Contents of the same test should generate source maps with the [email protected]

"use strict";
[].map((function(v) {
  return v + 1;
}));

//# sourceMappingURL=fixture.map

//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbImZpeHR1cmUuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IkFBQUE7QUFBQSxDQUFDLElBQUksQUFBQyxFQUFDLFNBQUEsQ0FBQTtPQUFLLENBQUEsQ0FBQSxFQUFJLEVBQUE7QUFBQSxFQUFDLENBQUE7QUFBQSIsImZpbGUiOiJmaXh0dXJlLmpzIiwic291cmNlUm9vdCI6Ii9ob21lL3gvdG1wL2d1bHAtdHJhY2V1ci9maXh0dXJlIiwic291cmNlc0NvbnRlbnQiOlsiW10ubWFwKHYgPT4gdiArIDEpIl19

I'm not sure about the use case of this;

// [...]
if (file.sourceMap) {
    fileOptions.sourceMaps = true;
}
// [...]

(extract from https://github.com/sindresorhus/gulp-traceur/blob/v0.14.0/index.js#L25 )

Setting the sourceMaps options to true is actually making traceur process the sourceMaps itself no ? (see https://github.com/google/traceur-compiler/wiki/SourceMaps)

Chrome 38.0.2125 (Windows 7) ERROR
Uncaught Error: Module name "path" has not been loaded yet for context: _. Use require([])
http://requirejs.org/docs/errors.html#notloaded
at /myproject/node_modules/requirejs/require.js:141

When I switch back to 0.13.0 it works...

But the app runs without problems...

Any ideas?

The source maps generated by gulp-sourcemaps are invalid. Source maps generated by the traceur command do work correctly.

For example trying to step into the constructor on on this line does not work with the gulp generated source map. If I generate the source map with traceur --out app.js --source-maps file bootstrap.js I can step into the constructor.

For some reason, the mappings array remains empty.

Traceur provides the ability to trace a single file and build all of its dependencies into one file. I'm not sure if that would make sense or not for this plugin.

One API for using this is described here - aaronfrost/grunt-traceur#21 (comment).

Thinking further about this, it seems to go against the principles of gulp though so perhaps we should ignore this?

the sourceMap option doesn't work anymore, post-traceur version 0.0.50. Was this a change related to this package, or traceur itself?

Please help me understand if I am wrong, but when I hook this up to a gulp watch, it essentially throws an exception and breaks the stream (hence stops watching since its a single process.) I see you are forwarding errors, but for whatever reason it seems syntax errors in your ES6 code still throw exceptions and break the watch, I wonder if wrapping the traceur.compile call in a try catch and forwarding the error from that would solve the problem, are you open to a PR or am I just misunderstanding something?

Hello,

There is a decent chance I'm doing it wrong, but it's worth a bug report anyway I think :).

If I compile a simple this simple ES6 module with traceur 0.0.31 directly I get significantly different output than when using gulp-traceur.

On a simple static HTML test page (with the traceur-runtime.js of course) the manually compiled version seems to work great. The gulp-traceur version I have not been able to get running.

core/thing.js

export class Thing {
    constructor(config) {
        console.log("Thing loaded.");
    }
}

app.js

import { Thing } from './core/thing'


export class App {
    constructor(config) {
        this.thing = Thing()
        console.log("Yip, I'm here.");
    }
}

traceur --out manual-build.js app.js core/thing.js

System.register("core/thing", [], function() {
  "use strict";
  var __moduleName = "core/thing";
  var Thing = function Thing(config) {
    console.log("Thing loaded.");
  };
  ($traceurRuntime.createClass)(Thing, {}, {});
  return {get Thing() {
      return Thing;
    }};
});
System.register("app", [], function() {
  "use strict";
  var __moduleName = "app";
  var Thing = System.get("core/thing").Thing;
  var App = function App(config) {
    this.thing = Thing();
    console.log("Yip, I'm here.");
  };
  ($traceurRuntime.createClass)(App, {}, {});
  return {get App() {
      return App;
    }};
});
System.get("app" + '');
System.get("core/thing" + '');

gulp

"use strict";
var __moduleName = "thing";
var Thing = function Thing(config) {
  console.log("Thing loaded.");
};
($traceurRuntime.createClass)(Thing, {}, {});
module.exports = {
  get Thing() {
    return Thing;
  },
  __esModule: true
};

"use strict";
var __moduleName = "app";
var Thing = require('./core/thing').Thing;
var App = function App(config) {
  this.thing = Thing();
  console.log("Yip, I'm here.");
};
($traceurRuntime.createClass)(App, {}, {});
module.exports = {
  get App() {
    return App;
  },
  __esModule: true
};

"use strict";
var __moduleName = "section_nav_controller";

index.html (test file)

<!DOCTYPE html>
<html>
<head>
    <title>Test</title>

    <script src="libs/traceur-runtime/traceur-runtime.js"></script>

    <script type="text/javascript" src="manual-build.js"></script>
</head>
<body>
    <script>
        var config = {
        };

        console.log("Inside the script module.");

        // Bizarre module fetching syntax from the traceur compiler..
        var App = System.get("../app/app").App;

        window.app = new App(config);
    </script>
</body>
</html>

Regardless of what variant of running gulp-traceur I get an error fromevents.js`:

Code such as the following won't work within my Gulpfile.

gulp.task('default', function () {
    return gulp.src('src/*.js')
        .pipe(sourcemaps.init())
        .pipe(traceur())
        .pipe(concat('all.js'))
        .pipe(sourcemaps.write())
        .pipe(gulp.dest('dist'));
});

Even trying to selectively take out parts I suspected were perhaps depreciated did not fix the problem:

gulp.task "js", ->
  return gulp.src './app/assets/es6js/**/*.js'
    # .pipe plugins.sourcemaps.init()
    .pipe plugins.traceur()
    # .pipe plugins.concat 'main.js'
    # .pipe plugins.sourcemaps.write()
    .pipe gulp.dest( 'app/assets/js' ) 
    # .pipe( plugins.filter( '**/*.js' ) )
    # .pipe( reload( stream: true ) )

The exact error I get is an unhandled 'error' event for a JS file that only has let a = 2; defined:

I use gulp-sourcemaps but the sourceMaps my files have are not transmitted to traceur.

From traceur source code, we read the input source maps from the options https://github.com/google/traceur-compiler/blob/master/src/Compiler.js#L224 but this option is not populated as in gulp-traceur we create the compiler before receiving files.

I fixed my build by removing the early creation of the compiler and changed this line this way:

var compiler = new traceur.NodeCompiler(objectAssign({modules: 'commonjs', inputSourceMap: file.sourceMap}, opts));
var ret = compiler.compile(file.contents.toString(), file.relative, file.relative, file.base);

I am using traceur 0.0.87 and gulp-traceur 0.17.0

Today I needed to hand-craft a gulp plugin similar to this one as I needed to dynamically calculate a module name (moduleName option) based on the input file path.

Would you be open to suggestion of supporting moduleName being a function that would be executed with the input file path (or the whole vinyl file) to calculate module name as string?

I specifically want to use traceur to use async/await. As far as I understand, this needs to be enabled by passing experimental flag to traceur.

Over here https://github.com/sindresorhus/gulp-traceur#traceuroptions it states that you should just pass whatever options you want to pass to the traceur compiler to the constructor of the gulp-traceur task. As you can see, I did this in my setup.

gulp.task('trac', function () {
    return gulp.src('./scripts/**/*.js')
        .pipe(traceur({experimental: true}))
        .on('error', function (err) {
          console.error('Error', err.message);
        })        
        .pipe(sourcemaps.init())
        .pipe(sourcemaps.write())
        .pipe(gulp.dest('./dist/js')); 
});

To test the setup, I copied this code I found on the interwebs into my files:

function promisingOperation() {
    return new Promise(function(resolve, reject) {
        setTimeout(function() {
            if( Math.round(Math.random()) ){
                resolve('Success!');
            }
            else{
                reject('Failure!');
            }
        }, 1000);
    });
}

(async function () {
    var message = await promisingOperation();
    console.log(message);
})(); 

But when the gulp task runs, it gives me this output:

Error filename:line:char: Semi-colon expected, which points to just after the await statement.
So it seems to me like it's not enabling the experimental features correctly?

Every time I try to transpile a JS file it breaks when it's has the "inline" option, AMD and CJS options are working fine. When I use traceur in the command line it works fine.

This is the error I got.

events.js:72
        throw er; // Unhandled 'error' event
              ^
TypeError: Cannot call method 'replace' of undefined
    at InlineModuleTransformer.getTempVarNameForModuleName (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:13434:33)
    at InlineModuleTransformer.wrapModule (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:17912:25)
    at InlineModuleTransformer.transformModule (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:13452:25)
    at Module.transform (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:6122:26)
    at InlineModuleTransformer.transformAny (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:11621:27)
    at FromOptionsTransformer.append (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:22181:55)
    at eval (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:21125:16)
    at Array.every (native)
    at FromOptionsTransformer.transform (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:21124:30)
    at Compiler.treeToTree (eval at <anonymous> (/Users/cabrera/htdocs/gulp-core-slim-sass-es6/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:17), <anonymous>:22437:41)

similar to gulp-ruby-sass please support sourcemapPath option.
my ES6 files with standard .js extension are kept at app/scripts and generated ES5 files with extension .js are kept in .tmp/scripts.
both app/* and ./tmp/* are exposed in -order- to browser-sync server and browser get confused where to get source files.
with sourcemapPath I could create a virtual path (scripts/src -> app/scripts) to source files that could point to app/scripts

gulp task:

var gulp = require('gulp');
var traceur = require('gulp-traceur');

gulp.task('default', function () {
    return gulp.src('src/test.js')
        .pipe(traceur({sourceMaps:true, blockBinding:true, experimental:true}))
        .pipe(gulp.dest('dist'));
});

with test.js looking like this:

{
  let x = 1;
}
console.log('Hello ${x}');

produces the es5 file in the "dist" directory but no sourcemap. No exception has been thrown.

This works fine:

traceur --source-maps --block-bonding true --out dist/test.js src/test.js 

Running the following:

gulp.task('default', function(){
  gulp.src('js/**/*.js')
    .pipe(plumber())
    .pipe(sourcemaps.init())
    .pipe(traceur())
    .pipe(sourcemaps.write('.'))
    .pipe(gulp.dest('dist/js'));
});

Gives me the map files but the names and mapping keys are empty in the map files:

..."names":[],"mappings":""...

and I can't set any breakpoints. Am I missing something?

As it's no possible to concat to one file with no modules it's good to support input source map. So it will be possible to concat first (and get a source map) then traceur with input source map and get compilled file with new source map.

Latest traceur is 0.0.74. This plugin requires 0.0.58

Hi,
is there any way to get mapped stack traces when error is thrown?

I tried following example code and ended with source maps generated, but it would be nice if these source maps could be used to map error stack traces to original locations. Is there any way to achieve that?

I read this article describing how to achieve that with babel transpiler. I tried the same with traceur but it didn't work.

gulp.task('default', function () {
    return gulp.src('src/*.js')
        .pipe(sourcemaps.init())
        .pipe(traceur())
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest('dist'));
});

Thanks for reply.

Traceur v0.0.66 was just released. Careful though – it looks like there have been breaking changes, as simply updating package.json causes the tests to fail (not sure why; else I would have submitted a patch).

I added this comment to the end of another issue, but maybe it wasn't seen because that issue was already closed.

I created a Github repo to demonstrate the problem. I made it as simple as possible. My gulpfile matches the example in the documentation with one exception, I don't want to concatenate files. I want a separate sourcemap file for each .js file in the src directory. Run "gulp" and notice that no .map files get created.

https://github.com/mvolkmann/gulp-traceur-demo.git

This is blocking some ongoing work I'm doing on angular to get fix some of the issues with webkit/javascriptcore.

Thanks!

From the package.json I see that the version of Traceur being used is 0.0.58.
As of now, Traceur is already at 0.0.72.

Since new features and bug fixes have been introduced with the newer versions of Traceur, when will the project update the version of this dependency?

I would've forked and tried to update it myself, but I have never worked with this codebase to be comfortable doing it.

Could the module expose (or include) the traceur runtime in some way, much like the traceur module does. So I can do something like:

var traceur = require('gulp-traceur')

gulp.task('traceur', function () {
  return gulp.src([traceur.runtime, './src/**.js']) // <- Include the file I need.
    .pipe(traceur({ modules: false }))
    .pipe(gulp.dest('dest/traceur'))
})

['/node_modules/gulp-traceur/node_modules/traceur/bin/traceur-runtime.js', './src/**.js'] is just not as pretty.

I can get gulp-traceur to generate sourcemap files, but I haven't been able to get them to work in Chrome or Firefox. When I look at a .js file in the debugger, I see the generated ES5 code, not the original ES6 code. Here's a snippet from my gulpfile.js that generates both the ES5 and sourcemap files:

gulp.task('transpile', ['jshint'], function () {
  return gulp.src(paths.jsNext).
    pipe(plumber()).
    pipe(changed(buildDir, {extension: '.js'})).
    pipe(sourceMaps.init()).
    pipe(traceur({experimental: true})).
    //pipe(sourceMaps.write()). // doesn't work!
    pipe(sourceMaps.write('.')). // works
    pipe(gulp.dest(buildDir));
});

This generates ES5 .js files in a "build" directory where my index.html expects to find them.
It also generates .js.map files in the same location as the corresponding .js files.

I wonder if it has anything to do with this. At the bottom of one of my generated .js files, filters.js, I see this:

//# sourceMappingURL=../share/filters.js.map

That is a correct path to filters.js.map. Inside that file I see this:

{"version":3,"sources":["share/filters.js", ...

That is not a correct path back to filters.js because it is missing the "../" part.

Depends on google/traceur-compiler#583

Hi,
If I use traceur with the --out filename parameter, the compiler resolves all dependencies and puts them in a single output file. How would I use gulp traceur to do the same? I'm using gulp-traceur 0.5.0 and the {modules: 'register'} option. This works fine, but it does not resolve dependencies.

This would be useful for first-time users to understand the output format.

Could one combine it with a Browserify gulp process to browserify ES6 modules?

Also Traceur needs an update, which should with some luck work out of the box (no big API changes I don't believe).

Some suggestions!

I am trying to use gulp-traceur to watch my files and generate a concatenated, compiled file with modules of type 'register'. However, the compiled file generated is not working and is inconsistent with the output file generated when running traceur from the command line:

My directory structure:

app/app.js
app/modules/home.js

app/app.js
import {homeModule} from './modules/home/home';

app/modules/home.js
export var homeModule = angular.module("Home", []);

This is generated from gulp-traceur:

System.register((void 0), [], function() {
  "use strict";
  var homeModule = System.get("modules/home/home").homeModule;
  var appModule = angular.module("App", ["ui.router"]);
  return {};
});

Note the (void 0), which is generating a message of 'TypeError: module name must be a string, not undefined' in the browser. Grunt-traceur had this error also and fixed it here:

aaronfrost/grunt-traceur@954c18b

I attempted to fix this by the same general approach but was also having ordering issues of how the modules were added to the compiled file.

Compiling from traceur CLI works fine with the following:

traceur app/app.js --out app/dist/cli.js --modules=register

and generates an output file of (note the module names populated with relative pathing to my output file)

System.register("../modules/home/home", [], function() {
  "use strict";
  var __moduleName = "../modules/home/home";
  var homeModule = angular.module("Home", []);
  return {get homeModule() {
      return homeModule;
    }};
});
System.register("../app", [], function() {
  "use strict";
  var __moduleName = "../app";
  var homeModule = System.get("../modules/home/home").homeModule;
  var appModule = angular.module("App", ["ui.router"]);
  return {};
});
System.get("../app" + '');

Not sure if this is a matter of versions with traceur itself. Current gulp-traceur uses 0.0.58 and I am using 0.0.72 from the CLI.

/home/user/project/node_modules/gulp-traceur/index.js:40
this.emit('error', new gutil.PluginError('gulp-traceur', errs.join('\n'), {
^

TypeError: errs.join is not a function
at DestroyableTransform._transform (/home/user/project/node_modules/gulp-traceur/index.js:40:66)
at DestroyableTransform.Transform._read (/home/user/project/node_modules/gulp-traceur/node_modules/readable-stream/lib/_stream_transform.js:184:10)
at DestroyableTransform.Transform._write (/home/user/project/node_modules/gulp-traceur/node_modules/readable-stream/lib/_stream_transform.js:172:12)
at doWrite (/home/user/project/node_modules/gulp-traceur/node_modules/readable-stream/lib/_stream_writable.js:237:10)
at writeOrBuffer (/home/user/project/node_modules/gulp-traceur/node_modules/readable-stream/lib/_stream_writable.js:227:5)
at DestroyableTransform.Writable.write (/home/user/project/node_modules/gulp-traceur/node_modules/readable-stream/lib/_stream_writable.js:194:11)
at write (/home/user/project/node_modules/vinyl-fs/node_modules/readable-stream/lib/_stream_readable.js:623:24)
at flow (/home/user/project/node_modules/vinyl-fs/node_modules/readable-stream/lib/_stream_readable.js:632:7)
at DestroyableTransform.pipeOnReadable (/home/user/project/node_modules/vinyl-fs/node_modules/readable-stream/lib/_stream_readable.js:664:5)
at emitNone (events.js:67:13)

Need some way to support module loading. Since traceur only converts import statements to requires, and browserify expects only a single entry point. It means in essence you can't use traceur except for concating files yourself. Need a solution for this.

I'm trying to use the import feature in ES6 and use a Google material design component in my website. In my scripts.js file I have
import {MDCDialog, MDCDialogFoundation, util} from '@material/dialog';

[EDIT] When I run traceur in gulp I get the following error:

MultipleErrors in plugin 'gulp-traceur' Message:
scripts.js:1188:5: Unexpected reserved word import
scripts.js:1188:12: Semi-colon expected

What am I doing wrong? Thank you!

With "0.14.0"

 var ctxName = createPrivateName();

TypeError: undefined is not a function
    at out (/home/one/github/encore-ui-template/node_modules/gulp-traceur/node_modules/traceur/bin/traceur.js:538:17)
    at Object.<anonymous> (/home/one/github/encore-ui-template/node_modules/gulp-traceur/node_modules/traceur/bin/traceur.js:641:3)
    at Module._compile (module.js:456:26)
    at Object.<anonymous> (/home/one/github/encore-ui-template/node_modules/gulp-traceur/node_modules/traceur/src/node/traceur.js:24:8)
    at Module._compile (module.js:456:26)
    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 Module.require (module.js:364:17)
    at require (module.js:380:17)

I haven't been able to get source maps to work.
I set the option sourceMaps to true, but don't get any maps.
I traced through the code in index.js and saw this:

if (ret.generatedSourceMap && file.sourceMap) {
applySourceMap(file, ret.generatedSourceMap);
}

I do have a value for ret.generatedSourceMap, but I don't have a value for file.sourceMap.
I don't know if I've stumbled across a bug or if these is something else I need to do to make that get set.

It would be nice to compile files without modules (if the are not used) and since without 'use strict' as it done in troucer.

current version in package.json
~0.0.49 won't auto update

Hi, I get the following error while installing the package:

[20:11:54] ~/Projects/wdc-web> npm install -S gulp-traceur
npm http GET https://registry.npmjs.org/gulp-traceur
npm http 304 https://registry.npmjs.org/gulp-traceur
npm http GET https://registry.npmjs.org/gulp-util
npm http GET https://registry.npmjs.org/object-assign
npm http GET https://registry.npmjs.org/through2
npm http GET https://registry.npmjs.org/traceur/0.0.74
npm http GET https://registry.npmjs.org/vinyl-sourcemaps-apply
npm http 304 https://registry.npmjs.org/gulp-util
npm http 304 https://registry.npmjs.org/through2
npm http 304 https://registry.npmjs.org/object-assign
npm http 304 https://registry.npmjs.org/traceur/0.0.74
npm http 304 https://registry.npmjs.org/vinyl-sourcemaps-apply
npm http GET https://registry.npmjs.org/source-map
npm http GET https://registry.npmjs.org/readable-stream
npm http GET https://registry.npmjs.org/xtend
npm http GET https://registry.npmjs.org/chalk
npm http GET https://registry.npmjs.org/dateformat
npm http GET https://registry.npmjs.org/lodash._reinterpolate
npm http GET https://registry.npmjs.org/lodash
npm http GET https://registry.npmjs.org/lodash.template
npm http GET https://registry.npmjs.org/minimist
npm http GET https://registry.npmjs.org/multipipe
npm http GET https://registry.npmjs.org/vinyl
npm http GET https://registry.npmjs.org/rsvp
npm http GET https://registry.npmjs.org/commander
npm http GET https://registry.npmjs.org/regexpu/0.3.0
npm http GET https://registry.npmjs.org/semver
npm http GET https://registry.npmjs.org/source-map-support
npm http 304 https://registry.npmjs.org/readable-stream
npm http 304 https://registry.npmjs.org/xtend
npm http 304 https://registry.npmjs.org/chalk
npm http 304 https://registry.npmjs.org/lodash._reinterpolate
npm http 304 https://registry.npmjs.org/dateformat
npm http 304 https://registry.npmjs.org/lodash
npm http GET https://registry.npmjs.org/core-util-is
npm http GET https://registry.npmjs.org/isarray/0.0.1
npm http GET https://registry.npmjs.org/string_decoder
npm http GET https://registry.npmjs.org/inherits
npm http 304 https://registry.npmjs.org/lodash.template
npm http 304 https://registry.npmjs.org/minimist
npm http 304 https://registry.npmjs.org/multipipe
npm http 304 https://registry.npmjs.org/vinyl
npm http 304 https://registry.npmjs.org/commander
npm http 304 https://registry.npmjs.org/semver
npm http 304 https://registry.npmjs.org/core-util-is
npm http GET https://registry.npmjs.org/supports-color
npm http GET https://registry.npmjs.org/ansi-styles
npm http GET https://registry.npmjs.org/has-ansi
npm http GET https://registry.npmjs.org/escape-string-regexp
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npm http 304 https://registry.npmjs.org/isarray/0.0.1
npm http GET https://registry.npmjs.org/lodash.defaults
npm http GET https://registry.npmjs.org/lodash.escape
npm http GET https://registry.npmjs.org/lodash._escapestringchar
npm http GET https://registry.npmjs.org/lodash.templatesettings
npm http GET https://registry.npmjs.org/lodash.keys
npm http GET https://registry.npmjs.org/lodash.values
npm http GET https://registry.npmjs.org/duplexer2/0.0.2
npm http GET https://registry.npmjs.org/clone
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npm http 304 https://registry.npmjs.org/string_decoder
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npm http GET https://registry.npmjs.org/meow
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npm http 304 https://registry.npmjs.org/rsvp
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npm http GET https://registry.npmjs.org/jsesc
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npm http 200 https://registry.npmjs.org/esprima-fb/-/esprima-fb-7001.1.0-dev-harmony-fb.tgz
npm http 304 https://registry.npmjs.org/jsesc
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npm ERR! Error: invalid version: 7001.0001.0000-dev-harmony-fb
npm ERR!     at validVersion (/usr/lib/nodejs/read-package-json/read-json.js:573:40)
npm ERR!     at final (/usr/lib/nodejs/read-package-json/read-json.js:323:23)
npm ERR!     at /usr/lib/nodejs/read-package-json/read-json.js:139:33
npm ERR!     at cb (/usr/lib/nodejs/slide/lib/async-map.js:48:11)
npm ERR!     at /usr/lib/nodejs/read-package-json/read-json.js:251:40
npm ERR!     at fs.js:268:14
npm ERR!     at /usr/lib/nodejs/graceful-fs/graceful-fs.js:103:5
npm ERR!     at Object.oncomplete (fs.js:107:15)
npm ERR! If you need help, you may report this log at:
npm ERR!     <http://bugs.debian.org/npm>
npm ERR! or use
npm ERR!     reportbug --attach /home/oleksandr/Projects/wdc/src/main/webapp/npm-debug.log npm

npm ERR! System Linux 3.11.0-12-generic
npm ERR! command "/usr/bin/nodejs" "/usr/bin/npm" "install" "-S" "gulp-traceur"
npm ERR! cwd /home/oleksandr/Projects/wdc/src/main/webapp
npm ERR! node -v v0.10.15
npm ERR! npm -v 1.2.18
npm http 304 https://registry.npmjs.org/cls
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /home/oleksandr/Projects/wdc/src/main/webapp/npm-debug.log
npm ERR! not ok code 0

Traceur is kind of special in the way that is usually used be several pieces in the whole project: gulp build, karma tests, runtime. All those different consumers should be using the same version of traceur, otherwise we might get wired run-time inconsistencies.

We had a (loongish) discussion about this in karma-runner recently and the conclusion was to move to peer dependencies:
https://github.com/karma-runner/karma-traceur-preprocessor/blob/master/package.json#L21

Could we have the same change for gulp-traceur so one can have only one version of traeur shared in the whole project?