Use the console to see available methods on an object?

Question

Is there any way I can use the console to see the methods available on a JS object?

I'm thinking of something like this:

> var myArray = [1,2,3];
  undefined
> myArray
  [1, 2, 3]
> myArray.logme = function() { console.log(this); };
  function () { console.log(this); }
> myArray
  [1, 2, 3]

The second time I type myArray, I would like to see the fact that the logme() method is now available.

I want to know the answer in order to explore unfamiliar JS objects more easily.

If you're referring to Chrome's console, then you could simply type `myArray.` (with the dot) this will reveal `logme` along with all other Array methods — juco, Mar 06 '13 at 14:20
Have a look a this q/a. http://stackoverflow.com/questions/5523747/equivalent-of-pythons-dir-in-javascript — Paolo, Mar 06 '13 at 14:26
@juco - that's cool, thank you. I don't suppose you know any way to see just the non-Array-prototype methods, though? — Richard, Mar 06 '13 at 14:27

score 8 · Accepted Answer · edited May 23 '17 at 12:19

8

You can use

console.dir(myArray);

and you will get an expandable/inspectable display like this, including custom properties and the prototype object:

_{(from https://stackoverflow.com/a/14537759/1048572, see also What's the difference between console.dir and console.log?)}

edited May 23 '17 at 12:19

Community

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answered Mar 06 '13 at 17:00

Bergi

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score 1 · Answer 2 · answered Mar 06 '13 at 14:30

If you're in Chrome and you could use something like the following (fairly crude) check for if a property is a function:

function showMethods(obj) {
    console.log(Object.keys(obj).filter(function(prop) {
        return typeof el[prop] == 'function';
    }));
}

Then just call it as follows:

showMethods({a: 1, b: 2, c: function () {}}) // ['c']
showMethods({a: 1, b: 2}) // []
showMethods({a: 1, b: function() {}, c: function () {}}) // ['b', 'c']

Use the console to see available methods on an object?

2 Answers2