Monitor heap usage of a web page. Throw error when heap exceeds its limitations.

monitorHeap.js

function monitorHeap({MAX_BYTES = 100, MAX_PERCENT = 90} = {}) {
    if (!window.performance || !window.performance.memory || !window.requestAnimationFrame) { return; }

    const MB = 1048576;
    const MAX_MEMORY = MAX_BYTES * MB;
    const MAX_PERCENTILE = MAX_PERCENT / 100;


    function heapcop() {
        const { usedJSHeapSize, jsHeapSizeLimit } = performance.memory;

        // Check if we've exceeded absolute memory limit
        if (usedJSHeapSize > MAX_MEMORY) {
            const error = new Error(`Exceeded memory maximum limit (${MAX_BYTES})`);

            error.code = 'EXCEEDED_MEMORY_ERROR';
            error.details = { used_heap_size: Math.round(usedJSHeapSize / MB) };

            throw error;
        }

        // Check if we've exceeded relative memory limit for client
        if (usedJSHeapSize > MAX_PERCENTILE * jsHeapSizeLimit) {
            const limit = Math.round(jsHeapSizeLimit / MB);
            const error = new Error(`Memory usage exceeded ${100 * MAX_PERCENT}% of ${limit}MB`);

            error.code = 'EXCEEDED_MEMORY_ERROR';
            error.details = {
                used_heap_size: Math.round(usedJSHeapSize / MB),
                heap_size_limit: limit
            };

            throw error;
        }

        // Only alert once
        requestAnimationFrame(heapcop);
    }

    requestAnimationFrame(heapcop);
}