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node.jsecmascript-6ecmascript-harmonyshebang

Can I specify es6 inside node js file

In order to use es6, we pass the harmony flag in the command line

node --harmony myscript.js

Is there a way to do this from inside the file, such as use harmony?

#! /usr/bin/node
use harmony

class MyScript {
    constructor (options) {
        this.options = options;
    }
    get options () {
        return this.options
    }
}
Solution

  • If your intention is to do this just so that you can run the script directly like ./myscript.js you could use this:

    #!/bin/sh
':' //; exec node --harmony "$0" "$@";

class MyScript {
    constructor (options) {
        this.options = options;
    }
    get options () {
        return this.options
    }
}

    I got the polyglot trick from the blog Obscure Javascript.

    If your intention is to be able to have another script started without --harmony be able to require this script, then this trick will not work.