ES6

Use

The ES6 syntax is the module syntax that will be part of the EMCAScript 6 standard currently in development. Because ES6 syntax is not valid in ES5 it requires compilation to use. Steal brings along Traceur to act as the ES6 compiler, which it does on the fly. When developing you won't even notice that it is loaded, and when built your modules are compiled down to ES5.

ES6 uses the keywords import and export for importing and exporting respectively. For example:

import can from "can";

This will import can from the can module, assuming it is the default exported value. If a module exports several values you can specify which to import using curly braces. Take an example of a Math module that exports several functions to do operations; it might be defined like so:

export function add(a, b) {
  return a + b;
}

export function subtract(a, b) {
  return a - b;
}

To import one or more of these exported values use curly braces in your module like so:

import { add, subtract } from "math";

You can export any type of value, like a normal var:

export var foo = "bar";

If you want to export a single value you can do so using the default keyword like so:

export default function add(a, b){
  return a + b;
}

Because Traceur is a full ES6 to ES5 compiler you can use many ES6 features beyond just module loading. Listing these is beyond the scope of this document, but you can check out many of the language features Traceur supports here.

Browser Support

The ES6 syntax is only available in IE9+. The Tracer Runtime requires Object.defineProperty. PhantomJS 1.x is also not supported due to limited support for getters and setters.