Source Maps on files with export statements have "throw SyntaxError"

[jgable]

I'm experiencing some source maps being off by about 3-4 lines consistently when compiling modules of non trivial size. A full example can be seen by following directions over at ModuleLoader/es6-module-loader#91 (Note that es6-module-loader uses version 0.0.9 of traceur).

I cloned this repo locally and tried to add a unit test to figure out whether it was this project or maybe a misuse by the module loader but am hitting a roadblock because when parsing a file with an export (or default) keyword there is a syntax error generated in the code.

Example Input

import { hello } from 'test1';

export var things = {
    'one': 1,

    updateThing: function (name, val) {
        this[name] = val;

        if (name === 'bingo') {
            console.log('bingo was his name o');

            this[name] += ' was his name o';
        }
    }
};

export default {
    things: things
};

Output

import 'test1';
(function() {throw SyntaxError("Unexpected token export");})();
var things = {
  'one': 1,
  updateThing: function(name, val) {
    this[name] = val;
    if (name === 'bingo') {
      console.log('bingo was his name o');
      this[name] += ' was his name o';
    }
  }
};
(function() {throw SyntaxError("Unexpected token export");})();
(function() {throw SyntaxError("Unexpected token default");})();
{
  things: things;
}
;

Full unit test I was trying to run is along these lines:

// FILE: /test/unit/codegeneration/SourceMap.js
var fs = require('fs'),
  path = require('path');
test('SingleFileWithExports', function () {
    var filename = 'sourceMap1.js';
    var src = fs.readFileSync(path.join(__dirname, 'fixture', 'sourceMap1.js')).toString();
    var tree = parse(filename, src);

    var generator = new SourceMapGenerator({file: filename});
    var options = {sourceMapGenerator: generator, showLineNumbers: false};
    var actual = TreeWriter.write(tree, options);

    var consumer = new SourceMapConsumer(options.sourceMap);
    //console.log(actual);
    //console.log(consumer);

    var sourceContent = consumer.sourceContentFor(filename);
    assert.equal(sourceContent, src);
  });

[arv]

export is only allowed in Module. Not in Script.

Make sure you are using parser.parseModule and not parser.parseScript.

[jgable]

An import is allowed in a script but an export is not? That seems odd. There is a unit test directly below mine I took as an example that uses an import statement.

[arv]

import was allowed in Script for while. The spec draft no longer allows it but we haven't updated our code yet.

[johnjbarton]

I am reopening this as a way to track:

1. Can we give a better result than output with throw embedded?
2. Disallow import in Script.
3. Can we provide a direct message "export not allowed in Script"? I've hit this several times and I predict it will be the number one problem with new users of modules.
4. Better api for transcoders.

[johnjbarton]

@jgable how did you get the output you show? It does not seem to come from the unit test code.

[jgable]

@arv The parseModule worked like a charm.

@johnjbarton I just did a console.log(actual) (it's commented out in my unit test example above) and when I ran make test/unit it spits it out.

[johnjbarton]

Issue #753 is item 2 on my list above.