How can I make console.log show the current state of an object?

Question

I think you're looking for console.dir().

console.log() doesn't do what you want because it prints a reference to the object, and by the time you pop it open, it's changed. console.dir prints a directory of the properties in the object at the time you call it.

The JSON idea below is a good one; you could even go on to parse the JSON string and get a browsable object like what .dir() would give you:

console.log(JSON.parse(JSON.stringify(obj)));

What I usually do if I want to see it's state at the time it was logged is I just convert it to a JSON string.

console.log(JSON.stringify(a));

Vanilla JS:

@evan's answer seems best here. Just (ab)use JSON.parse/stringify to effectively make a copy of the object.

console.log(JSON.parse(JSON.stringify(test)));

JQuery specific solution:

You can create a snapshot of an object at a certain point in time with jQuery.extend

console.log($.extend({}, test));

What is actually happening here is jQuery is creating a new object with the test object's content, and logging that (so it will not change).

AngularJS (1) specific solution:

Angular provides a copy function that can be used to the same effect: angular.copy

console.log(angular.copy(test));

Vanilla JS wrapper function:

Here is an function which wraps console.log but will make a copy of any objects before logging them out.

I wrote this in response to a few similar but less robust functions in the answers. It supports multiple arguments, and will not try to copy things if they are not regular objects.

function consoleLogWithObjectCopy () {
  var args = [].slice.call(arguments);
  var argsWithObjectCopies = args.map(copyIfRegularObject)
  return console.log.apply(console, argsWithObjectCopies)
}

function copyIfRegularObject (o) {
  const isRegularObject = typeof o === 'object' && !(o instanceof RegExp)
  return isRegularObject ? copyObject(o) : o
}

function copyObject (o) {
  return JSON.parse(JSON.stringify(o))
}

example usage: consoleLogWithObjectCopy('obj', {foo: 'bar'}, 1, /abc/, {a: 1})

That > Object in the console, isn't only showing the current state. It actually is deferring reading the object and it's properties until you expand it.

For example,

var test = {a: true}
console.log(test);
setTimeout(function () {
    test.a = false; 
    console.log(test);
}, 4000);

Then expand the first call, it will be correct, if you do it before the second console.log returns

using Xeon06's hint, you may parse his JSON in an object, and here is the log function I now use to dump my objects :

function odump(o){
   console.log($.parseJSON(JSON.stringify(o)));
}