疑问，这一系列的异步操作如何做同步化改造？有这个必要吗？

function step1(func){	
	process.nextTick(function(){
		console.log(‘step1‘);
		func(1);
	});
}
function step2(val, func){
	process.nextTick(function(){
		console.log(‘step2,‘ + val);
		func(val+1);
	});
}
function step3(val, func){
	process.nextTick(function(){
		console.log(‘step3,‘ + val);
		func(val+1);
	});
}
function step4(val, func){
	process.nextTick(function(){
		console.log(‘step4,‘ + val);
		func(val+1);
	});
}
step1(function(val1){
	step2(val1, function(val2){
		step3(val2, function(val3){
			step4(val3, function(val4){
				console.log(‘val4, ‘, val4);
			})
		})
	})
})