javascript - setTimeout函数中未指定延迟是否意味着零延迟？

Question

setTimeout函数中未指定延迟是否意味着零延迟？
也就是说，是这样的调用:

setTimeout(function() {
    //do something
}); // NOTE: no delay specified

等于:

setTimeout(function() {
    //do something
}, 0); // NOTE: zero delay specified

？

Answer 1

正如 setTimeout documentation 中提到的，delay 是一个可选值，如果未指定，则将设置为 0。

delay Optional

The time, in milliseconds (thousandths of a second), the timer should wait before the specified function or code is executed. If this parameter is omitted, a value of 0 is used, meaning execute "immediately", or more accurately, as soon as possible. Note that in either case, the actual delay may be longer than intended; see Reasons for delays longer than specified below.