OR 语句被忽略

Question

我试图仅在按下某些键时才触发我的 masterFunction。但是，无论单击哪个按钮，它都会被调用。即使控制台日志显示不同的密钥。

谁能指点一下？

//Update display on keydown event
addEventListener('keydown', (e) => {
    pressedKey = event.key;
    console.log(pressedKey);
    keyDownOperatorMapping(e);
});

let keyDownOperatorMapping = (e) => {
if (pressedKey === "+" || "-" || "*" || "Enter" || "Backspace" || "." || "/") {
masterFunction(e);
} 
};

示例：https://jsfiddle.net/rykawgs9/

Answer 1

您必须输入要比较的变量。在您的情况下，pressedKey:

if (pressedKey === "+" || pressedKey === "-" || pressedKey === "*" || pressedKey === "Enter" || pressedKey === "Backspace" || pressedKey === "." || pressedKey === "/")
...

Answer 2

因为你现在的状态是

嘿是 pressedKey equal is "+" 或者是 "-" is true 或者 //继续

因为长度大于 1 的字符串总是 1，所以它总是 return true 你的条件总是正确的

所以一种存档方式

addEventListener('keydown', (e) => {
  pressedKey = event.key;
  console.log(pressedKey);
  keyDownOperatorMapping(e);
});

let keyDownOperatorMapping = (e) => {
  const keys = ["+", "-", "*", "Enter", "Backspace", ".", "/"]
  if (keys.includes(pressedKey)) {
    console.log("Found");
  }
};

Answer 3

您可以通过将可搜索键添加到数组中来稍微减少代码，然后检查数组 includes 是否为输入的键。

const allowed = ['+', '-', '*', 'Enter', 'Backspace', ',', '/'];

document.addEventListener('keydown', (e) => {

  const { key } = e;

  if (allowed.includes(key)) {

    // masterFunction(e)
    console.log(key);

  }

});

其他文档

Destructuring assignment

OR 语句被忽略

OR statement being ignored

javascript