First the question:

Where can I find the external-helpers.js script, or how can I build the external-helpers for Babel 6?

In Babel 5.x, I was able to use the externalHelpers option, which required including external-helpers.js, which used to be in the babel-core package. Moving on to Babel 6, I see that external-helpers is now external-helpers-2 plugin. This does the job of including the relevant babelHelper calls in my transpiled code, but that is it; I need the actual helper definitions!

In the issue add missing build script for external-helpers.js, it is suggested to " build it yourself with the CLI". I don't see any CLI options that seem to deal with building external helpers.

First the question:

Where can I find the external-helpers.js script, or how can I build the external-helpers for Babel 6?

In Babel 5.x, I was able to use the externalHelpers option, which required including external-helpers.js, which used to be in the babel-core package. Moving on to Babel 6, I see that external-helpers is now external-helpers-2 plugin. This does the job of including the relevant babelHelper calls in my transpiled code, but that is it; I need the actual helper definitions!

In the issue add missing build script for external-helpers.js, it is suggested to " build it yourself with the CLI". I don't see any CLI options that seem to deal with building external helpers.

• javascript
• babeljs

• Please read tag descriptions. babel is for questions for a Python library with said name. – Felix Kling Commented Nov 15, 2015 at 8:36
• Doh! Thanks, @FelixKling. – Lokua Commented Nov 15, 2015 at 9:52

2 Answers 2

I managed to build the external-helpers.js with the babel-core package and the Node REPL:

var helperBuilder = require('./lib/tools/build-external-helpers');
fs.writeFileSync('external-helpers.js', helperBuilder());

I imagine that, depending on your situation, you could also build the external helpers file by build script (Grunt, Gulp, etc.)

The CLI mand referred to in the issue you mention is babel-external-helpers, which is part of the babel-cli npm package. With the babel-cli package installed, running babel-external-helpers --help gives the following self-explanatory output:

Usage: babel-external-helpers [options]

Options:

-h, --help                   output usage information
-l, --whitelist [whitelist]  Whitelist of helpers to ONLY include
-t, --output-type [type]     Type of output (global|umd|var)

It simply outputs the file to stdout, so to print the code to a file, you do babel-external-helpers [options] > babel-helpers.js.