function 如何从 JavaScript 中的另一个 function 访问变量值？

Question

 let count = 0; function increment(){ count += 1; console.log(count); } function decrement(){ count -= 1; console.log(count); } increment(); decrement();

Calling increment() will give count = 1 and then calling decrement() will give count = 0 . How does the second function get the value of count from the first function?

Answer 1

You have to return that value from a function and pass count as argument to the functions:

let count = 0;

function increment(count){ 
    count += 1;
    console.log(count);
    return count; 
}

function decrement(count){ 
    count -= 1;
    console.log(count); 
    return count;
}

var value = increment(count);
value = decrement(count);

value = decrement(increment(count)); //no change of course