node.js 中的空 for 循环行为

Question

I am trying to test for loop behavior in node.js. In Javascript/node.js for loop is synchronous but what if their is no statement in the loop.

For Example:

 console.log("START") for(var i=0; i<100000000;i++){ } console.log("END")

When i run above code in node.js it just prints:

START
END

And the execution completes.

But if there is a statement in the loop, it executes complete loop and then ends:

 console.log("START") for(var i=0; i<100000000;i++){ console.log("LOOP "+i); } console.log("END")

The output is:

START
LOOP 0
LOOP 1
....
....
....
LOOP 99999999
END

So what happens if there is no statement in the for loop in node.js ?

Answer 1

Even if there's no statement, yes, there are still some calculation like initialization , condition , and/or final-expression .

Besides, sometimes people do use for without a statement. You can take a look at MDN: Using for without a statement .

Answer 2

Finally i got it. For loop is always synchronous whether it is JavaScript or Node.js. And node.js does not skip an empty loop.

Executed below code:

console.log("START")
for(var i=0; i<10000000000;i++){
}
console.log(i);
console.log("END")

The output is:

START
10000000000
END