Code to test how much memory is available with Node.js

node-js-memory-test.js

// Source: https://github.com/Data-Wrangling-with-JavaScript/nodejs-memory-test

//
// Small program to test the maximum amount of allocations in multiple blocks.
// This script searches for the largest allocation amount.
//

//
// Allocate a certain size to test if it can be done.
//
function alloc (size) {
    const numbers = size / 8;
    const arr = []
    arr.length = numbers; // Simulate allocation of 'size' bytes.
    for (let i = 0; i < numbers; i++) {
        arr[i] = i;
    }
    return arr;
};

//
// Keep allocations referenced so they aren't garbage collected.
//
const allocations = []; 

//
// Allocate successively larger sizes, doubling each time until we hit the limit.
//
function allocToMax () {

    console.log("Start");

    const field = 'heapUsed';
    const mu = process.memoryUsage();
    console.log(mu);
    const gbStart = mu[field] / 1024 / 1024 / 1024;
    console.log(`Start ${Math.round(gbStart * 100) / 100} GB`);

    let allocationStep = 100 * 1024;

    while (true) {
        // Allocate memory.
        const allocation = alloc(allocationStep);

        // Allocate and keep a reference so the allocated memory isn't garbage collected.
        allocations.push(allocation);

        // Check how much memory is now allocated.
        const mu = process.memoryUsage();
        const mbNow = mu[field] / 1024 / 1024 / 1024;
        console.log(`Allocated since start ${Math.round((mbNow - gbStart) * 100) / 100} GB`);
    }
};

allocToMax();