Is there anything special about the init function in JavaScript objects?
In a lot of cod开发者_JAVA百科e, it's very common to see an init
function be declared, like so:
var someObject = {
// What is this for?
init: function () {
// Call here.
}
};
Are there anything particularly special about the init function that I should know?
For some frameworks perhaps (though prototype
and backbone
use initialize
instead), but there is nothing special about the init
functions in plain old javascript
Executive summary: Like others say - init
property is not magic in Javascript.
Longer story: Javascript objects are merely key->value storages. If you instantiate an object yourself then it's almost empty - it only inherits some properties from its constructor's prototype. This is a sample dump from Chrome inspector:
> obj = {}
Object
+-__proto__: Object
|-__defineGetter__: function __defineGetter__() { [native code] }
|-__defineSetter__: function __defineSetter__() { [native code] }
|-__lookupGetter__: function __lookupGetter__() { [native code] }
|-__lookupSetter__: function __lookupSetter__() { [native code] }
|-constructor: function Object() { [native code] }
|-hasOwnProperty: function hasOwnProperty() { [native code] }
|-isPrototypeOf: function isPrototypeOf() { [native code] }
|-propertyIsEnumerable: function propertyIsEnumerable() { [native code] }
|-toLocaleString: function toLocaleString() { [native code] }
|-toString: function toString() { [native code] }
|-valueOf: function valueOf() { [native code] } > obj = {}
-- as you can see, there is no init
on the list. The closest to init
would be constructor
property, which you can read about e.g. here.
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