我在哪里可以使用 JS Switch case 语句来转换这些多个 If/Else 语句？答案

【问题标题】：Where can I use the JS Switch case statement to convert these multiple If/Else statements?我在哪里可以使用 JS Switch case 语句来转换这些多个 If/Else 语句？
【发布时间】：2020-06-29 23:28:00
【问题描述】：

您好，提前感谢您提供的任何帮助或见解。

我正在开发一款 Space Battle 游戏，我想知道是否有办法使用 JavaScript SWITCH case 语句来替换我代码中的许多 If/Else 语句。
我不知道switch (expression) 从哪一行开始。
switch (expression) 适合这个程序吗？

// Battle Function = Set up a function that "Holds" the battle

let shipsBattle = (ship1, ship2) => {

  let ships = [ship1, ship2]; // put the ships into an array
  let attack = false;
  let attacking = 0;
  let beingAttacked = 1;
  let temp;
  console.log("%c Attack Begins =================", "font-size: 30px");
  while (ships[beingAttacked].hull > 0) { //While the hull is greater than 0...Keep attacking


    // Attacking Sequence

    if (ships[beingAttacked].hull > 0) {

      console.log("\n"); // Console log the attack information
      console.log(
        `%c ${ships[attacking].name} attacked ${ships[beingAttacked].name}`,
        "color: purple; border: 1px solid grey; font-size: 18px;"
      );

      attack = ships[attacking].attack(); // Generate the attack on the enemy ship
      if (attack === true) {
        ships[beingAttacked].hull -= ships[attacking].firePower; //Increase Fire power
        console.log(
          `%c Attack Successful! ${ships[beingAttacked].name} Hull: ${ships[beingAttacked].hull}`,
          "color: green; font-weight: bold; font-size: 16px;"
        );
      } else {
        console.log(
          `%c Attack Unsuccessful! ${ships[beingAttacked].name} Hull: ${ships[beingAttacked].hull}`,
          "color: red; font-size: 16px;"
        );
      }

      if (ships[beingAttacked].hull <= 0) { // Check if the ship being attacked is still alive
        console.log(
          `%c ${ships[beingAttacked].name} has been destroyed`,
          "color: red; border: 1px solid grey; font-size: 16px;"
        );
        if (ships[beingAttacked] === ussSchwartz) {

          alert("Game Over!!!"); //If the USS Ship is being attacked alert player Game is Over
        } else if (
          ships[beingAttacked].name === alienShips[alienShips.length - 1].name
        ) {
          alert(
            `%c ${ships[beingAttacked].name} destroyed!\nAlien fleet has been destroyed!\nyou have been victorious`,
            "color: green;"
          );
        } //If USS destroys alien fleet, then alert player of victory
        else {
          game.userResponse = prompt(
            `${alienShips[game.targetShip].name} destroyed!!\n${
              ussSchwartz.name
            } Hull: ${
              ussSchwartz.hull
            }\nWould you like to ATTACK the next ship or RETREAT from battle?`,
            ""
          );
          game.targetShip += 1; //PROMPT PLAYER IF THEY WANT TO CONTINUE OR RETREAT
          checkUserPrompt();
          return;
        }
      } else {

        temp = attacking; // Change the attacking/attacked ships
        attacking = beingAttacked;
        beingAttacked = temp;
      }
    }
  }
};

【问题讨论】：

switch 仅适用于将相同表达式与不同值进行相等比较的情况。它对于大于/小于比较或测试不同的表达式没有用。我在这里看不到任何可以用开关代替的东西。

标签： javascript arrays if-statement switch-statement

【解决方案1】：

在我看来，您正在检查ships[beingAttacked].hull > 0，然后进行一些真假计算。之后，您将更新 ships[beingAttacked] 并在 ships[beingAttacked].hull < 0 上进行比较

因为这样的开关看起来不合适，因为它通常在我们定义了一些东西并且我们没有在每个 else if 中进行不同的比较时使用。

我猜，您要做的是进行代码清理。我建议你：

为您的用例创建流程图并尝试识别通用代码。或可重用的逻辑。
将该代码移动到单独的函数中，这将提高代码的可读性和重复利用率。

【讨论】：