Eloquent Javascript Chapter 10: Modules

when writing a module's interface...

- prefer functions to stateful objects - follow existing conventions if possible - consider how your output will be composed with other functions

scripts vs. ES modules

Scripts: bindings in global scope, cannot directly reference other scripts Modules: get their own scope, support import & export keywords to declare their dependencies and interface Module support started in 2015

Why might you compile your code into a different JS version?

So you can write in Typescript, but the code can then be converted to older JS versions so more browsers can use it

NPM

a repository of javascript packages (node package manager)

What can you use 'export' on in a module?

functions, class, bindings

How to import everything from a module?

import * as local_scope_name from "path/to/module";

How to import from a module?

import {export_name as local_scope_name} from "path/to/module";

How to import the default from a module?

omit the braces import local_scope_name from "path/to/module";

CommonJS Modules

require function & exports object the pre-ESmodule solution. A regular script, but it has access to two bindings that it uses for module interaction: `require` and `exports`

bundlers

tools that combine modularized programs into a single file

minifiers

tools that make a javascript file smaller for lower latency