middleware-perf-throttle.js

import perf    from '../lib/perf.js';
const THRESHOLD = 83; // ~ 5 animation frames

const slowLog = (action, duration) => {
    (requestAnimationFrame || setTimeout)(() => {
        console.warn(`[perf] action ${action.type} took ${duration.toFixed(2)}ms`, {
            mean:      perf.mean(action.type),
            sdev:      perf.sdev(action.type),
            samples:   perf.getEntriesByName(action.type).length,
        });
    }, 0);
};
let correction = 0;
perf.onFPS((fps) => {
    correction = 60 - fps;
}, 500);

const perfMiddleware = store => next => action => {
    if (!action._delayed && correction > 5) {
        action._delayed = correction;
        setTimeout(() => {
            store.dispatch(action);
        }, Math.round(correction));
        return store.getState();
    }
    perf.start(action.type);

    let result = next(action);

    perf.end(action.type);
    if (perf.duration(action.type) > THRESHOLD) {
        slowLog(action, perf.duration(action.type));
    }
    return result;
};

export default perfMiddleware;