lasso-babel-transform

Lasso.js transform that uses Babel to transpile ES6 code to ES5.

Prerequisites

This transform requires Lasso v2+

Installation

lasso 2.x/3.x, babel 7.x, lasso-babel-transform 2.x

npm install lasso-babel-transform @babel/core

lasso 2.x/3.x, babel 6.x, lasso-babel-transform 1.x

npm install lasso-babel-transform@1

Usage

By default, this plugin will look for a .babelrc while traversing up the root directory of the packages and will transpile any files that have the .js or .es6 extension. If a .babelrc file does not exist, it will attempt to look for a .babelrc-browser file. If neither of those files exist, this plugin will look in the package.json for a babel property.

You can specify different file extensions with the extensions option in the transform's config (shown below). Files are cached in memory by default. You can use memoryCachedExtensions to remove caching on some files if you prefer. To save memory the cache is flushed after idleCacheFlushTimeout (default: 10 minutes).

require('lasso').configure({
    require: {
        transforms: [
            {
                transform: 'lasso-babel-transform',
                config: {
                    extensions: ['.marko', '.js', '.es6'], // Enabled file extensions. Default: ['.js', '.es6']
                    memoryCachedExtensions: ['.js', '.es6'], // Enabled memory caching for these file extensions. Default: same of 'extensions'
                    idleCacheFlushTimeout: 20 * 60 * 1000, // FLushese the cache to save memory after 20 mins. Default 10 minutes.
                }
            }
        ]
    }
});

Global babel options

Alternatively, babel options can be provided directly via the config. Note: Specifying babel options directly will cause all files to be transpiled with these options (regardless of what is specified in the package's .babelrc, .babelrc-browser, or babel property in the package.json).

require('lasso').configure({
    require: {
        transforms: [
            {
                transform: 'lasso-babel-transform',
                config: {
                    // directly specify babel options
                    babelOptions: {
                        presets: [ "@babel/preset-env" ]
                    }
                }
            }
        ]
    }
});

Configuring Babel

You will want to put a .babelrc or .babelrc-browser file at the root of each package that has any JavaScript files that should be transpiled by Babel. For example:

my-module/.babelrc:

{
    "exclude": ["excluded/**"],
    "presets": [ "@babel/preset-env" ]
}

As mentioned above, you can also opt to use the babel property to the package.json.

my-module/package.json:

{
    "name": "my-module",
    ...
    "babel": {
        // babel config goes here
    }
}

You will need to install any Babel plugins enabled in your babel config. For example:

npm install @babel/preset-env --save

Debugging

Add this at the beginning of your main file:

require('raptor-logging').configure({
    loggers: {
        'lasso-babel-transform': 'DEBUG', // or Info
        'lasso-babel-transform/cache': 'DEBUG'
    }
});