Javascript：如何获取函数的值？

Question

I am making a quick game where a player damages a enemy npc. I have a function below that does the calculation for the damage, but I can't get the console log to say i'm doing "X" amount of damage. What am I doing wrong? Instead, it just pulls up the function statement, but I want it to give me the functions value!

var damage = function() {
    return Math.floor(Math.random() * 5 + 1);
    };

I'm calling my function in another code properly, but when I try to console log the damage in that other code, I get a error.

function attackButton() {
    darkwarrior.hp = darkwarrior.hp - damage();
    console.log(darkwarrior.hp);
    console.log(damage);

Answer 1

If you run console.log(damage()); you will get the "X" amount of damage instead of the function statement. So you could change attackButton() function to be:

function attackButton() {
    var damageDealt = damage();
    darkwarrior.hp = darkwarrior.hp - damageDealt;
    console.log(darkwarrior.hp);
    console.log(damageDealt);

Answer 2

I'm not sure to understand, you want to log the result? If so, you can do that:

var damage = function() {
    return Math.floor(Math.random() * 5 + 1);
    };

console.log(damage());

EDIT:

you forgot the (). + the value will not be the same if you don't put it in a variable:

function attackButton() {
    var amount = damage()
    darkwarrior.hp = darkwarrior.hp - amount;
    console.log(darkwarrior.hp);
    console.log(amount);
}

Answer 3

you just have to use an expression to assign the value to a variable. Then log it. Then return it.

 var damage = function() { var num = Math.floor(Math.random() * 5 + 1); console.log(num); return num; }; damage(); 

Answer 4

Something like this should work for you.

 function NPC(startingLife, name) { this.hp = startingLife; this.name = name } NPC.prototype.takeDamage = function(amount) { this.hp = Math.max(this.hp - amount, 0); if (this.hp == 0) { console.log(this.name + " Dies"); } return this.hp; }; function damage() { return Math.floor(Math.random() * 5 + 1); } var darkwarrior = new NPC(4, 'Dark Warrior'); function attackButton() { var amount = damage(); darkwarrior.takeDamage(amount); console.log("Dark Warrior took " + amount + " points of damage"); } document.querySelector('#attack-button').addEventListener("click", attackButton); 

 <button id="attack-button">ATTACK!</button> 

Answer 5

You are just returning the value instead of printing it. You should instead replace return with console.log(