我正在学习如何衡量性能,并且想使用一些大约需要1-2秒的代码来进行计算。
我使用了下面摘自Mozilla的这段代码,但我想知道是否有人可以帮助我进行更简洁的操作。不必“有意义”。
const iterations = 50;
const multiplier = 1000000000;
function calculatePrimes(iterations, multiplier) {
var primes = [];
for (var i = 0; i < iterations; i++) {
var candidate = i * (multiplier * Math.random());
var isPrime = true;
for (var c = 2; c <= Math.sqrt(candidate); ++c) {
if (candidate % c === 0) {
// not prime
isPrime = false;
break;
}
}
if (isPrime) {
primes.push(candidate);
}
}
return primes;
}
function doPointlessComputationsWithBlocking() {
var primes = calculatePrimes(iterations, multiplier);
pointlessComputationsButton.disabled = false;
console.log(primes);
}
答案 0 :(得分:1)
以“需要时间”为目的进行操作的最简单方法是只在一段时间内什么也不做:
function wait(seconds) {
var start = new Date();
//empty while loop until the required amount of time has passed
while((new Date() - start) / 1000 < seconds);
}
var begin = performance.now();
console.log("start");
wait(2);
console.log("finish in", performance.now() - begin, "ms");
如果您不确定需要的时间,则可以随意增加或修改等待时间:
function wait(seconds) {
// add or subtract up to 50%
seconds *= Math.random() + 0.5;
var start = new Date();
while((new Date() - start) / 1000 < seconds);
}
var begin = performance.now();
console.log("start");
wait(2);
console.log("finish in", performance.now() - begin, "ms");