slate/scripts/memory-burn.js

// Source
// https://github.com/Data-Wrangling-with-JavaScript/nodejs-memory-test/blob/master/index.js
// 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("[ starting memory burn  ]");

    const field = "heapUsed";
    const mu = process.memoryUsage();
    console.log(mu);
    const gbStart = mu[field] / 1024 / 1024 / 1024;
    console.log(
        `[ memory burn           ] ${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(`Total allocated       ${Math.round(mbNow * 100) / 100} GB`);
        console.log(
            `[ allocated since start ] ${Math.round((mbNow - gbStart) * 100) /
                100} GB`
        );

        // Infinite loop, never get here.
    }

    // Infinite loop, never get here.
}

allocToMax();