socket.io發出返回相同的值

Question

這里有一個enemyHealth問題，有人可以告訴我，為什么我每次從客戶端attack發射時， enemyHealth和userHealth每次發射始終保持94，而不是每次攻擊時減少6？ 僅在首次點擊時減少。

socket.on('attack', () => {

    var userDamage = 6;

    var enemyDamage = 6;

    var userHealth = 100;
    var enemyHealth = 100;

    var userDmg = userDamage;
    var enemyDmg = enemyDamage;

    userHealth -= enemyDmg;
    enemyHealth -= userDmg;

    console.log(enemyHealth);

});

Answer 1

每個attack事件上的enemyHealth和userHealth保持相同的原因是，這些變量是在attack事件本身中聲明的，因此，每次attack事件發生時，它們的值將始終相同。

解決您的問題的一種方法是，只需簡單地將enemyHealth和用戶userHealth的聲明和初始化enemyHealth attack事件處理程序，如下所示：

// Declare these variables outside of the attach handler so that their updated 
// values are retained between attack events
var userHealth = 100;
var enemyHealth = 100;

socket.on('attack', () => {

    var userDamage = 6;    
    var enemyDamage = 6;

    // Remove the variable declarations from inside the attack event
    // var userHealth = 100;
    // var enemyHealth = 100;

    var userDmg = userDamage;
    var enemyDmg = enemyDamage;

    userHealth -= enemyDmg;
    enemyHealth -= userDmg;

    // Now this value goes down each time the attach event occours
    console.log(enemyHealth);

});