如何在 JavaScript 中一起减去两件事

How to minus two things together in JavaScript...?

本文关键字：两件 JavaScript 一起      更新时间：2023-09-26

我正在做一个游戏，我需要扣除适量的分数。我的这个陈述不起作用（播放器电源）部分。

function checkCol(cell, row){
    var color = map[row][cell];
    console.log(color);
    if (color == "g") {
        alert("Green");
        playerPower -= onGrass - passengerBayPower
    } else if (color == "b") {
        alert("Brown");
        playerPower -= onRock - passengerBayPower
    } else if (color == "w") {
        alert("White");
        playerPower -= onIce - passengerBayPower
    }

-= 然后 -有问题吗？

你可以通过以下方式简化它：

var color = map[row][cell];
var diff = 0;
    console.log(color);
    if (color == "g") {
        alert("Green");
        diff = onGrass - passengerBayPower
    } else if (color == "b") {
        alert("Brown");
        diff = onRock - passengerBayPower
    } else if (color == "w") {
        alert("White");
        diff = onIce - passengerBayPower
    }
    playerPower -= diff;

让我们给你的变量一些值。假设playerPower是 10，onGrass是 2，passengerBayPower是 4。你可能期望答案是10 - 2 - 4 = 4，对吧？错。。。

playerPower -= onGrass - passengerBayPower

对应...

playerPower = playerPower - (onGrass - passengerBayPower)
            = playerPower - onGrass + passengerBayPower
                                // ^^^ using basic mathematics

这意味着您可以10 - 2 + 4 = 12

要修复，请使用 onGrass + passengerBayPower ，或完全删除passengerBayPower并将其放在末尾：

playerPower -= passengerBayPower;

因为这在所有情况下都很常见。

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