Babel Post-Install Hook Idea

es6guardian.js

#!/usr/bin/env node
try {
  require('./')
} catch (err) {
  var name = require('path').dirname(__dirname)
  console.log('es6 not supported in your environment, downgrading '+name+' to es5')
  var lazyRequire = require('lazy-require')
  lazyRequire('babel', function(err){
    if ( err ) {
      process.stderr.write(err.stack.toString()+'\n')
      process.exit(-1)
      return
    }
    require('child_process').exec('./node_modules/.bin/babel lib --out-dir es5; rm -Rf lib; mv es5 lib', {stdio:'inherit'}, function(err){
      if ( err ) {
        process.stderr.write(err.stack.toString()+'\n')
        process.exit(-1)
        return
      }
      console.log(name+' was sucessfully downgraded from es6 to es5')
    })
  })
}

package.json

{
  "dependencies": {
    "lazy-require": "^2.0.0"
  },
  "scripts": {
    "postinstall": "./es6guardian.js"
  }
}

Nice idea. :)

I've abandoned the above postcompile idea for a precompile then fallback idea.

See https://github.com/bevry/esnextguardian and https://github.com/bevry/base for the latest way I do this.