Earlier quoted context omitted.
Hate to be a wet blanket, but that second code sample won't work. The function doesn't return anything so $ === undefined. Even if it did, this in that context is bound to the global object, so is the same as setting a variable without var or let. A proper example of IIFE for lexical scoping would be something like this: var numbers = ""; (function(){ for (var i=0; i Nowadays of course you could just use let instead…
Hate to dry off the blanket but they just forgot the `new` keyword for `this` ;) var $ = new (function() { this.version = '1.2.3'; })(); console.log($.version); // '1.2.3' EDIT: Or if you really want to abuse the spec var $ = (function() { if (!(this instanceof arguments.callee)) return new arguments.callee(); this.version = '1.2.3' })(); console.log($.version); // '1.2.3'
var $ = (function(){ this.version = '1.2.3'; return this; }).call({})
console.log($.version); //1.2.3