Available

Node.js will inject these for you - you do not need to do explicity import/require.

See a full list in the docs

  • https://nodejs.org/api/globals.html

Global

Almost never use this.

This is for builtins and is like window.

global

Sample from the REPL:

> global

<ref *1> Object [global] {
  global: [Circular *1],
  clearInterval: [Function: clearInterval],
  clearTimeout: [Function: clearTimeout],
  setInterval: [Function: setInterval],
  setTimeout: [Function: setTimeout] {
    [Symbol(nodejs.util.promisify.custom)]: [Function (anonymous)]
  },
  queueMicrotask: [Function: queueMicrotask],
  clearImmediate: [Function: clearImmediate],
  setImmediate: [Function: setImmediate] {
    [Symbol(nodejs.util.promisify.custom)]: [Function (anonymous)]
  }
}

Process

Info on the current running process.

process

You can view the entire result in the REPL.

Here are some common uses:

process.env.Foo
process.exit(1)

https://nodejs.org/api/process.html

Console

As in the browser, you can log in a Node.js app.

console.log('Foo')

Require

Find and use modules in the current module.

require

require('foo')

Paths

These will give an error in a REPL.

Directory name

__dirname

Filename

__filename

Module

Info about the current module and methods for making is consumable by imports.

module

Sample from the REPL:

> module

Module {
  id: '<repl>',
  path: '.',
  exports: {},
  parent: undefined,
  filename: null,
  loaded: false,
  children: [],
  paths: [
    '/Users/mcurrin/repl/node_modules',
    '/Users/mcurrin/node_modules',
    '/Users/node_modules',
    '/node_modules',
    '/Users/mcurrin/.node_modules',
    '/Users/mcurrin/.node_libraries',
    '/usr/local/Cellar/node/14.3.0_1/lib/node'
  ]
}

Export

You must use this so that an object is available to import from another script.

export

Add an export line at the end of your script.

function foo () {}

class Bar () {}

// This is more modern and uses a cleaner hash.
export {
  foo,
  Bar
}
// Same as:
module.exports = {
  foo: foo,
  Bar: Bar
}

Or export in place:

export function foo () {}

export class Bar () {}

Not available

You can’t use anything browser-specific in Node.js.

window
document
fetch

You should avoid using window in general anyway as it allows a wider scope (permissions issue) and there maybe collissions. Only if your use an external script like for Google Analytics that needs you to put something on window.

You can use a polyfill such as node-fetch to allow use of fetch.