EnvironmentDetection

それぞれの環境における特徴点を洗い出したものが以下になります。

typeof *	Browser	Worker	Node	NW.js	Electron render	Electron main
window	object	-	-	object	object	-
self	object	object	-	object	object	-
global	-	-	object	object	object	object
GLOBAL	-	-	object	-	object	object
document	object	-	-	object	object	-
WorkerLocation	-	object	-	-	-	-
__dirname	-	-	string	-	string	string
__filename	-	-	string	-	string	string
setTimeout + ""	native	native	custom	native	native	custom
process.type	-	-	-	-	renderer	browser

これらのパズルを解きコンパクトにまとめたものが、WebModule.js の冒頭のコードになります。

var GLOBAL = (this || 0).self || global;

// --- environment detection -------------------------------
// https://github.com/uupaa/WebModule/wiki/EnvironmentDetection
(function() {

var hasGlobal     = !!GLOBAL.global;              // Node.js, NW.js, Electron
var processType   = !!(GLOBAL.process || 0).type; // Electron(render and main)
var nativeTimer   = !!/native/.test(setTimeout);  // Node.js, Electron(main)

GLOBAL.IN_BROWSER = !hasGlobal && "document"       in GLOBAL;
GLOBAL.IN_WORKER  = !hasGlobal && "WorkerLocation" in GLOBAL;
GLOBAL.IN_NODE    =  hasGlobal && !processType && !nativeTimer;
GLOBAL.IN_NW      =  hasGlobal && !processType &&  nativeTimer;
GLOBAL.IN_EL      =  hasGlobal &&  processType;

})();