CODEWITHSUNDEEP
javascriptjqueryobjectmethods
thom
thom

Reputation: 1041

How to get an object's methods?

Is there a method or propertie to get all methods from an object? For example:

function foo() {}
foo.prototype.a = function() {}
foo.prototype.b = function() {}

foo.get_methods(); // returns ['a', 'b'];

UPDATE: Are there any method like that in Jquery?

Thank you.

Upvotes: 104

Views: 135471

Answers (12)

DevTheJo
DevTheJo

Reputation: 2487

for me, the only reliable way to get the methods of the final extending class, was to do like this:

function getMethodsOf(obj){
  const methods = {}
  Object.getOwnPropertyNames( Object.getPrototypeOf(obj) ).forEach(methodName => {
    methods[methodName] = obj[methodName]
  })
  return methods
}

Upvotes: 9

sidanmor
sidanmor

Reputation: 5189

Get the Method Names:

var getMethodNames = function (obj) {
    return (Object.getOwnPropertyNames(obj).filter(function (key) {
        return obj[key] && (typeof obj[key] === "function");
    }));
};

Or, Get the Methods:

var getMethods     = function (obj) {
    return (Object.getOwnPropertyNames(obj).filter(function (key) {
        return obj[key] && (typeof obj[key] === "function");
    })).map(function (key) {
        return obj[key];
    });
};

Upvotes: 0

Matoeil
Matoeil

Reputation: 7289

The methods can be inspected in the prototype chain of the object using the browser's developer tools (F12):

  console.log(yourJSObject);

or more directly

  console.dir(yourJSObject.__proto__);

Upvotes: 6

Arturo Morales Rangel
Arturo Morales Rangel

Reputation: 141

the best way is:

let methods = Object.getOwnPropertyNames(yourobject);
console.log(methods)

use 'let' only in es6, use 'var' instead

Upvotes: 1

Kevin Beal
Kevin Beal

Reputation: 10849

In ES6:

let myObj   = {myFn : function() {}, tamato: true};
let allKeys = Object.keys(myObj);
let fnKeys  = allKeys.filter(key => typeof myObj[key] == 'function');
console.log(fnKeys);
// output: ["myFn"]

Upvotes: 5

Șerban Ghiță
Șerban Ghiță

Reputation: 1947

In Chrome is keys(foo.prototype). Returns ["a", "b"].

See: https://developer.chrome.com/devtools/docs/commandline-api#keysobjectenter image description here

Later edit: If you need to copy it quick (for bigger objects), do copy(keys(foo.prototype)) and you will have it in the clipboard.

Upvotes: 0

pstenstrm
pstenstrm

Reputation: 6489

You can use console.dir(object) to write that objects properties to the console.

Upvotes: 27

Sampson
Sampson

Reputation: 268344

In modern browsers you can use Object.getOwnPropertyNames to get all properties (both enumerable and non-enumerable) on an object. For instance:

function Person ( age, name ) {
    this.age = age;
    this.name = name;
}

Person.prototype.greet = function () {
    return "My name is " + this.name;
};

Person.prototype.age = function () {
    this.age = this.age + 1;
};

// ["constructor", "greet", "age"]
Object.getOwnPropertyNames( Person.prototype );

Note that this only retrieves own-properties, so it will not return properties found elsewhere on the prototype chain. That, however, doesn't appear to be your request so I will assume this approach is sufficient.

If you would only like to see enumerable properties, you can instead use Object.keys. This would return the same collection, minus the non-enumerable constructor property.

Upvotes: 20

Makram Saleh
Makram Saleh

Reputation: 8701

function getMethods(obj)
{
    var res = [];
    for(var m in obj) {
        if(typeof obj[m] == "function") {
            res.push(m)
        }
    }
    return res;
}

Upvotes: 79

Larry Osterman
Larry Osterman

Reputation: 16142

Remember that technically javascript objects don't have methods. They have properties, some of which may be function objects. That means that you can enumerate the methods in an object just like you can enumerate the properties. This (or something close to this) should work:

var bar
for (bar in foo)
{
    console.log("Foo has property " + bar);
}

There are complications to this because some properties of objects aren't enumerable so you won't be able to find every function on the object.

Upvotes: 48

Raynos
Raynos

Reputation: 169401

var methods = [];
for (var key in foo.prototype) {
    if (typeof foo.prototype[key] === "function") {
         methods.push(key);
    }
}

You can simply loop over the prototype of a constructor and extract all methods.

Upvotes: 1

Matt Greer
Matt Greer

Reputation: 62027

var funcs = []
for(var name in myObject) {
    if(typeof myObject[name] === 'function') {
        funcs.push(name)
    }
}

I'm on a phone with no semi colons :) but that is the general idea.

Upvotes: 2

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