How to write an ES6 class\module that can be used by NodeJS & Aurelia

Question

I'm trying to share some simple metadata classes between my nodeJS backend and an Aurelia front end. I can require and use the following from my node (v4.3) process:

"use strict";

class PersonMetadata {

    constructor() {
        this.relation = ["Spouse/partner", "Child", "Parent", "Other"];
    }
}

module.exports.PersonMetadata = PersonMetadata;

but it fails to load in the browser after being processed by the typical Aurelia front end build with:

Error: Cannot read property 'exports' of undefined

How can I structure a module with a class that can be shared between node & Aurelia?

Answer 1

Thought I'd reply with how I got this working. Since my server side node code doesn't currently get processed by gulp I created a shared ES6 class that is directly compatible with node v4.X:

"use strict";

class SharedMetadata {

    constructor() {
        this.myOptions = ["Democrat", "Republican", "Other"];
   }
}

exports.SharedMetadata = SharedMetadata;

This class can be use from node like this:

var SharedMetadata = require('../shared/SharedMetadata').SharedMetadata;

var sharedMetadata = new SharedMetadata();

For the front end this file is processed by the normal Aurelia build\transpile step, but the file will have an error with the exports statement.

So I added another gulp build step that runs only on the "shared" files after the transpile step that fixes up the errors and does a "proper" export:

gulp.task('transform-shared', function() {
    return gulp.src(paths.outputShared + '**/*.js')
        .pipe(replace(/exports\.(.*) = (.*);/g, "_export('$1', $2);"))
        .pipe(gulp.dest(paths.outputShared));
});

This replaces the exports statement with:

_export('SharedMetadata ', SharedMetadata );

Then the class can be used like any "normal" Aurelia front end class.