RequestIdleCallback-computeLayout.js

function computeLayout(idleDeadline) {
    var milliseconds = idleDeadline.timeRemaining();
    var haltTime = performance.now() + milliseconds;
  
    for (let i=lastIndex; i < queue.length; i++) {
        if (performance.now() > haltTime)
            break;
  
        // pseudocode
        x = R cosΦ sin(λ - λ₀)
        y = R (cosΦ₀ sinΦ - sinΦ₀ cosΦ cos(λ - λ₀))
        
        lastIndex = i;
    }
    
    // if not complete, ask for another notification
    if (lastIndex < queue.length-1)
        idleCallbackId = requestIdleCallback(computeLayout);
    else
        idleCallbackId = 0;
}