Is there any solution to get the function name of an object?
function alertClassOrObject (o) {
window.alert(o.objectName); //"myObj" OR "myClass" as a String
}
function myClass () {
this.foo = function () {
alertClassOrObject(this);
}
}
var myObj = new myClass();
myObj.foo();
for (var k in this) {...}
- there is no information about the className
or ObjectName
. Is it possible to get one of them?
This question is related to
javascript
Try this:
var classname = ("" + obj.constructor).split("function ")[1].split("(")[0];
Example:
function Foo () { console.log('Foo function'); }_x000D_
var Bar = function () { console.log('Bar function'); };_x000D_
var Abc = function Xyz() { console.log('Abc function'); };_x000D_
_x000D_
var f = new Foo();_x000D_
var b = new Bar();_x000D_
var a = new Abc();_x000D_
_x000D_
console.log('f', f.constructor.name); // -> "Foo"_x000D_
console.log('b', b.constructor.name); // -> "Function"_x000D_
console.log('a', a.constructor.name); // -> "Xyz"
_x000D_
All we need:
console.clear();_x000D_
function App(){ // name of my constant is App_x000D_
return {_x000D_
a: {_x000D_
b: {_x000D_
c: ()=>{ // very important here, use arrow function _x000D_
console.log(this.constructor.name)_x000D_
}_x000D_
}_x000D_
}_x000D_
}_x000D_
}_x000D_
const obj = new App(); // usage_x000D_
_x000D_
obj.a.b.c(); // App_x000D_
_x000D_
// usage with react props etc, _x000D_
// For instance, we want to pass this callback to some component_x000D_
_x000D_
const myComponent = {};_x000D_
myComponent.customProps = obj.a.b.c;_x000D_
myComponent.customProps(); // App
_x000D_
I was facing a similar difficulty and none of the solutions presented here were optimal for what I was working on. What I had was a series of functions to display content in a modal and I was trying to refactor it under a single object definition making the functions, methods of the class. The problem came in when I found one of the methods created some nav-buttons inside the modal themselves which used an onClick to one of the functions -- now an object of the class. I have considered (and am still considering) other methods to handle these nav buttons, but I was able to find the variable name for the class itself by sweeping the variables defined in the parent window. What I did was search for anything matching the 'instanceof' my class, and in case there might be more than one, I compared a specific property that was likely to be unique to each instance:
var myClass = function(varName)
{
this.instanceName = ((varName != null) && (typeof(varName) == 'string') && (varName != '')) ? varName : null;
/**
* caching autosweep of window to try to find this instance's variable name
**/
this.getInstanceName = function() {
if(this.instanceName == null)
{
for(z in window) {
if((window[z] instanceof myClass) && (window[z].uniqueProperty === this.uniqueProperty)) {
this.instanceName = z;
break;
}
}
}
return this.instanceName;
}
}
As this was already answered, I just wanted to point out the differences in approaches on getting the constructor of an object in JavaScript.
There is a difference between the constructor and the actual object/class name. If the following adds to the complexity of your decision then maybe you're looking for instanceof
. Or maybe you should ask yourself "Why am I doing this? Is this really what I am trying to solve?"
Notes:
The obj.constructor.name
is not available on older browsers.
Matching (\w+)
should satisfy ES6 style classes.
Code:
var what = function(obj) {
return obj.toString().match(/ (\w+)/)[1];
};
var p;
// Normal obj with constructor.
function Entity() {}
p = new Entity();
console.log("constructor:", what(p.constructor), "name:", p.constructor.name , "class:", what(p));
// Obj with prototype overriden.
function Player() { console.warn('Player constructor called.'); }
Player.prototype = new Entity();
p = new Player();
console.log("constructor:", what(p.constructor), "name:", p.constructor.name, "class:", what(p));
// Obj with constructor property overriden.
function OtherPlayer() { console.warn('OtherPlayer constructor called.'); }
OtherPlayer.constructor = new Player();
p = new OtherPlayer();
console.log("constructor:", what(p.constructor), "name:", p.constructor.name, "class:", what(p));
// Anonymous function obj.
p = new Function("");
console.log("constructor:", what(p.constructor), "name:", p.constructor.name, "class:", what(p));
// No constructor here.
p = {};
console.log("constructor:", what(p.constructor), "name:", p.constructor.name, "class:", what(p));
// ES6 class.
class NPC {
constructor() {
}
}
p = new NPC();
console.log("constructor:", what(p.constructor), "name:", p.constructor.name , "class:", what(p));
// ES6 class extended
class Boss extends NPC {
constructor() {
super();
}
}
p = new Boss();
console.log("constructor:", what(p.constructor), "name:", p.constructor.name , "class:", what(p));
Result:
If you use standard IIFE (for example with TypeScript)
var Zamboch;
(function (_Zamboch) {
(function (Web) {
(function (Common) {
var App = (function () {
function App() {
}
App.prototype.hello = function () {
console.log('Hello App');
};
return App;
})();
Common.App = App;
})(Web.Common || (Web.Common = {}));
var Common = Web.Common;
})(_Zamboch.Web || (_Zamboch.Web = {}));
var Web = _Zamboch.Web;
})(Zamboch || (Zamboch = {}));
you could annotate the prototypes upfront with
setupReflection(Zamboch, 'Zamboch', 'Zamboch');
and then use _fullname and _classname fields.
var app=new Zamboch.Web.Common.App();
console.log(app._fullname);
annotating function here:
function setupReflection(ns, fullname, name) {
// I have only classes and namespaces starting with capital letter
if (name[0] >= 'A' && name[0] <= 'Z') {
var type = typeof ns;
if (type == 'object') {
ns._refmark = ns._refmark || 0;
ns._fullname = fullname;
var keys = Object.keys(ns);
if (keys.length != ns._refmark) {
// set marker to avoid recusion, just in case
ns._refmark = keys.length;
for (var nested in ns) {
var nestedvalue = ns[nested];
setupReflection(nestedvalue, fullname + '.' + nested, nested);
}
}
} else if (type == 'function' && ns.prototype) {
ns._fullname = fullname;
ns._classname = name;
ns.prototype._fullname = fullname;
ns.prototype._classname = name;
}
}
}
Source: Stackoverflow.com