Node.js global variables
You can use global
like so:
global._ = require('underscore')
In Node.js, you can set global variables via the "global" or "GLOBAL" object:
GLOBAL._ = require('underscore'); // But you "shouldn't" do this! (see note below)
or more usefully...
GLOBAL.window = GLOBAL; // Like in the browser
From the Node.js source, you can see that these are aliased to each other:
node-v0.6.6/src/node.js:
28: global = this;
128: global.GLOBAL = global;
In the code above, "this" is the global context. With the CommonJS module system (which Node.js uses), the "this" object inside of a module (i.e., "your code") is not the global context. For proof of this, see below where I spew the "this" object and then the giant "GLOBAL" object.
console.log("\nTHIS:");
console.log(this);
console.log("\nGLOBAL:");
console.log(global);
/* Outputs ...
THIS:
{}
GLOBAL:
{ ArrayBuffer: [Function: ArrayBuffer],
Int8Array: { [Function] BYTES_PER_ELEMENT: 1 },
Uint8Array: { [Function] BYTES_PER_ELEMENT: 1 },
Int16Array: { [Function] BYTES_PER_ELEMENT: 2 },
Uint16Array: { [Function] BYTES_PER_ELEMENT: 2 },
Int32Array: { [Function] BYTES_PER_ELEMENT: 4 },
Uint32Array: { [Function] BYTES_PER_ELEMENT: 4 },
Float32Array: { [Function] BYTES_PER_ELEMENT: 4 },
Float64Array: { [Function] BYTES_PER_ELEMENT: 8 },
DataView: [Function: DataView],
global: [Circular],
process:
{ EventEmitter: [Function: EventEmitter],
title: 'node',
assert: [Function],
version: 'v0.6.5',
_tickCallback: [Function],
moduleLoadList:
[ 'Binding evals',
'Binding natives',
'NativeModule events',
'NativeModule buffer',
'Binding buffer',
'NativeModule assert',
'NativeModule util',
'NativeModule path',
'NativeModule module',
'NativeModule fs',
'Binding fs',
'Binding constants',
'NativeModule stream',
'NativeModule console',
'Binding tty_wrap',
'NativeModule tty',
'NativeModule net',
'NativeModule timers',
'Binding timer_wrap',
'NativeModule _linklist' ],
versions:
{ node: '0.6.5',
v8: '3.6.6.11',
ares: '1.7.5-DEV',
uv: '0.6',
openssl: '0.9.8n' },
nextTick: [Function],
stdout: [Getter],
arch: 'x64',
stderr: [Getter],
platform: 'darwin',
argv: [ 'node', '/workspace/zd/zgap/darwin-js/index.js' ],
stdin: [Getter],
env:
{ TERM_PROGRAM: 'iTerm.app',
'COM_GOOGLE_CHROME_FRAMEWORK_SERVICE_PROCESS/USERS/DDOPSON/LIBRARY/APPLICATION_SUPPORT/GOOGLE/CHROME_SOCKET': '/tmp/launch-nNl1vo/ServiceProcessSocket',
TERM: 'xterm',
SHELL: '/bin/bash',
TMPDIR: '/var/folders/2h/2hQmtmXlFT4yVGtr5DBpdl9LAiQ/-Tmp-/',
Apple_PubSub_Socket_Render: '/tmp/launch-9Ga0PT/Render',
USER: 'ddopson',
COMMAND_MODE: 'unix2003',
SSH_AUTH_SOCK: '/tmp/launch-sD905b/Listeners',
__CF_USER_TEXT_ENCODING: '0x12D732E7:0:0',
PATH: '/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:~/bin:/usr/X11/bin',
PWD: '/workspace/zd/zgap/darwin-js',
LANG: 'en_US.UTF-8',
ITERM_PROFILE: 'Default',
SHLVL: '1',
COLORFGBG: '7;0',
HOME: '/Users/ddopson',
ITERM_SESSION_ID: 'w0t0p0',
LOGNAME: 'ddopson',
DISPLAY: '/tmp/launch-l9RQXI/org.x:0',
OLDPWD: '/workspace/zd/zgap/darwin-js/external',
_: './index.js' },
openStdin: [Function],
exit: [Function],
pid: 10321,
features:
{ debug: false,
uv: true,
ipv6: true,
tls_npn: false,
tls_sni: true,
tls: true },
kill: [Function],
execPath: '/usr/local/bin/node',
addListener: [Function],
_needTickCallback: [Function],
on: [Function],
removeListener: [Function],
reallyExit: [Function],
chdir: [Function],
debug: [Function],
error: [Function],
cwd: [Function],
watchFile: [Function],
umask: [Function],
getuid: [Function],
unwatchFile: [Function],
mixin: [Function],
setuid: [Function],
setgid: [Function],
createChildProcess: [Function],
getgid: [Function],
inherits: [Function],
_kill: [Function],
_byteLength: [Function],
mainModule:
{ id: '.',
exports: {},
parent: null,
filename: '/workspace/zd/zgap/darwin-js/index.js',
loaded: false,
exited: false,
children: [],
paths: [Object] },
_debugProcess: [Function],
dlopen: [Function],
uptime: [Function],
memoryUsage: [Function],
uvCounters: [Function],
binding: [Function] },
GLOBAL: [Circular],
root: [Circular],
Buffer:
{ [Function: Buffer]
poolSize: 8192,
isBuffer: [Function: isBuffer],
byteLength: [Function],
_charsWritten: 8 },
setTimeout: [Function],
setInterval: [Function],
clearTimeout: [Function],
clearInterval: [Function],
console: [Getter],
window: [Circular],
navigator: {} }
*/
** Note: regarding setting "GLOBAL._", in general you should just do var _ = require('underscore');
. Yes, you do that in every single file that uses Underscore.js, just like how in Java you do import com.foo.bar;
. This makes it easier to figure out what your code is doing because the linkages between files are 'explicit'. It is mildly annoying, but a good thing. .... That's the preaching.
There is an exception to every rule. I have had precisely exactly one instance where I needed to set "GLOBAL._". I was creating a system for defining "configuration" files which were basically JSON, but were "written in JavaScript" to allow a bit more flexibility. Such configuration files had no 'require' statements, but I wanted them to have access to Underscore.js (the entire system was predicated on Underscore.js and Underscore.js templates), so before evaluating the "configuration", I would set "GLOBAL._". So yeah, for every rule, there's an exception somewhere. But you had better have a darn good reason and not just "I get tired of typing 'require', so I want to break with the convention".