Object litteral memory performance in JS

Question

Is object literal free memory when same object name recreate? what is effect on memory when I recreate same object name from object literal. e.g.

var objLit = {};
for(var i=0; i<5; i++){
    objLit['room'] = {};
    objLit['room'].name = "A",
    objLit['room'].class = 10
}

console.log(objLit['room']);

output is currect but what about 4 previews object literal which made by for loop. my question:

is all 4 object auto delete? is all 4 object reference auto delete?

You are overwriting `objLit.room` with a new Object at every pass of the loop. You want an Array. — StackSlave, Apr 20 '17 at 07:05
`objLit['room']` and `objLit.room` are the same thing. You only need to use the String version if your property does not comply with `.` Syntax, like when there is a space in your property name. See my example. — StackSlave, Apr 20 '17 at 07:15
Client Side JavaScript does not support `static` properties on most Browsers. You would have to use a class anyways. That's just a String. — StackSlave, Apr 20 '17 at 07:34

score 0 · Answer 1 · answered Apr 20 '17 at 07:59

I gave this a try in Chrome:

var objLit = {};

for(var i = 0; i < 500000000; i++){
    objLit['room'] = {};
    objLit['room'].name = "A",
    objLit['room'].class = 10
}

console.log(objLit['room']);

If the memory wasn't released, you'd expect the memory usage for that tab to keep growing while the loop was running.

This wasn't the case. Chrome does not consume more memory if the loop is 500000000 iterations long, than when it's 50 iterations long.

In other words, garbage collection gets rid of the previous value.
(In Chrome, but I'm sure other browsers behave the same way for an example like this.)

Object litteral memory performance in JS

1 Answers1