Example 8

Example 8: Recording heap allocations

Let's analyze the impact of closures on memory

You can see that 'eval' retains a reference on all the variables of the closure.

1. Start to record heap allocations
2. Start the creation of new closures
3. Analyze what is happening

Closures mantain hold on large string

Closures mantain hold only on small strings

Closures with eval

Stop and clear

---

'use strict';

var intervalId,
    closures = [];
    
function createLargeClosure() {
    var largeStr = new Array(1000000).join('x');
    return function lC() {
        return largeStr;
    };
}

function createSmallClosure() {
    var smallStr = 'x';
    var largeStr = new Array(1000000).join('x');
    return function sC() {
        return smallStr;
    };
}

function createEvalClosure() {
    var smallStr = 'x';
    var largeStr = new Array(1000000).join('x');
    return function eC() {
        eval('');
        return smallStr;
    };
}

function largeClosures() {
    stopInterval();
    intervalId = setInterval(function () {
        closures.push(createLargeClosure());
    }, 1000);
}

function smallClosures() {
    stopInterval();
        intervalId = setInterval(function () {
        closures.push(createSmallClosure());
    }, 1000);
    
}

function evalClosures() {
    stopInterval();
    intervalId = setInterval(function () {
        closures.push(createEvalClosure());
    }, 1000);
}

function stopInterval() {
    if (intervalId) {
        clearInterval(intervalId);
    }
    intervalId = null;
}

function clear() {
    closures.length = 0;
}

function stopAndClear(){
    stopInterval();
    clear();
}