In Step III: Concurrent Mode, I learn that: requestIdleCallback(func) will call the call back function when the browser is idle.
But in workLoop function, that while loop confused me.

function workLoop(deadline) { let shouldYield = false while (nextUnitOfWork && !shouldYield) { nextUnitOfWork = performUnitOfWork( nextUnitOfWork ) shouldYield = deadline.timeRemaining() < 1 } requestIdleCallback(workLoop) } 

My question is: if shoudYield is false, it means that the browser is busy, so we should stop calling the next unit of work.
But in this while loop, if shoudYield is false, the loop will continue and do the next unit of work. Why?