[Wallenstein]

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}
var bbo = 1;
var shbb = 1;
bb.onclick = async function() {
	console.log(shbb);
	if (shbb=1) {
		console.log('while1');
		while(bbo>0){
			bbo-=0.05;
			bb.style.opacity = bbo;
			await sleep(1);
			if (bbo<=0) {
				bbo = 0;
				shbb = 0;
				bb.style.opacity = bbo;
				console.log('while1 - complete');
				break;
			}
		}
	}
	if (shbb=0) {
		console.log('while2');
		while(bbo<=1){
			bbo+=0.05;
			bb.style.opacity = bbo;
			await sleep(1);
			if (bbo>=1) {
				bbo = 1;
				shbb = 1;
				bb.style.opacity = bbo;
				console.log('while2 - complete');
				break;
			}
		}
	}
}

Консоль:
1
while1
while1 - complete
0
while1
0
while1
0
while1
Вопрос: почему не доходит до while2? Ведь только он удовлетворяет условиям.