goog.module style

goog.module export styles

In a goog.module file, there are two distinct styles, based on the two styles of exports in ES6 modules. Note that unlike with ES6 modules, goog.module cannot use both styles in a single module; each goog.module file is considered to be using either a default export or named exports.

Default exports

In goog.module, a default export can be created by assigning directly to the export of a module, and is the most common export style:

goog.module('a.b.c.Foo');

class Foo {}

exports = Foo;

Named exports

Named exports from a goog.module can be defined in one of two ways, the first way is to make the exported name clear at the declaration site, like the following:

goog.module('d.e.f');

exports.value = 5;

class Foo {}
exports.Foo = Foo;

The other way to list all the exports at the end of the module, with a style similar to the revealing module pattern, like the following:

goog.module('d.e.f');

const value = 5;

class Foo {}

exports = {Foo, value};

Note that only object literals that contain only names can be used for named exports in this way, as that is the restriction for the similar syntax in ES6 module exports.

Destructuring imports

One advantage to using named exports is that they can be imported using destructuring imports to bring in the names of interest as unqualified names in the importing module, such as:

goog.module('x.y.z');

const {value} = goog.require('d.e.f');

alert(value);