获取对象或类的名称

Question

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?

Answer 1

Get your object's constructor function and then inspect its name property.

myObj.constructor.name

Returns "myClass".

Answer 2

Example:

 function Foo () { console.log('Foo function'); } var f = new Foo(); console.log('f', f.constructor.name); // -> "Foo" var Bar = function () { console.log('Anonymous function (as Bar)'); }; var b = new Bar(); console.log('b', b.constructor.name); // -> "Bar" var Abc = function Xyz() { console.log('Xyz function (as Abc)'); }; var a = new Abc(); console.log('a', a.constructor.name); // -> "Xyz" class Clazz { constructor() { console.log('Clazz class'); } } var c = new Clazz(); console.log('c', c.constructor.name); // -> "Clazz" var otherClass = class Cla2 { constructor() { console.log('Cla2 class (as otherClass)'); } } var c2 = new otherClass(); console.log('c2', c2.constructor.name); // -> "Cla2"

Answer 3

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;
        }
    }
}

JsFiddle

Answer 4

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:

Code: https://jsbin.com/wikiji/edit?js,console

Answer 5

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;
    }
}

Answer 6

试试这个：

var classname = ("" + obj.constructor).split("function ")[1].split("(")[0];

Answer 7

All we need:

1. Wrap a constant in a function (where the name of the function equals the name of the object we want to get)
2. Use arrow functions inside the object

 console.clear(); function App(){ // name of my constant is App return { a: { b: { c: ()=>{ // very important here, use arrow function console.log(this.constructor.name) } } } } } const obj = new App(); // usage obj.abc(); // App // usage with react props etc, // For instance, we want to pass this callback to some component const myComponent = {}; myComponent.customProps = obj.abc; myComponent.customProps(); // App

Answer 8

在运行时获取类名的最有效方法

let className = this.constructor.name