如何为switch语句中有意穿透的case安全修复ESLint no-fallthrough错误？

方法1：用ESLint认可的穿透标记注释 #

ESLint的no-fallthrough规则默认认可// falls through或/* falls through */这两种注释，用来标记这是有意的case穿透。你只需要把这个注释放在穿透case的最后，哪怕中间有功能注释，也要在功能注释后面补上它：

switch(num) {
  case 1:
    /*
      I also have comments in my code that explain functionality to non-developers.
    */
    // falls through
  case 2:
    return "if one or two";
  case 3:
    return "if three only";
}

方法2：临时关闭该代码块的规则 #

要是不想加特定注释，直接用ESLint的块级禁用语法，只在当前switch范围内关掉no-fallthrough规则就行：

/* eslint-disable no-fallthrough */
switch(num) {
  case 1:
    /*
      I also have comments in my code that explain functionality to non-developers.
    */
  case 2:
    return "if one or two";
  case 3:
    return "if three only";
}
/* eslint-enable no-fallthrough */

方法3：自定义ESLint的穿透注释规则 #

如果想让现有功能注释也能被ESLint识别为穿透标记，可以在ESLint配置文件（比如.eslintrc.js）里修改no-fallthrough规则，添加自定义的注释匹配关键词：

module.exports = {
  // 其他配置项...
  rules: {
    "no-fallthrough": ["error", {
      "commentPattern": "falls through|intentional fallthrough|针对非开发者的功能说明"
    }]
  }
};

只要你的注释里包含配置的关键词，ESLint就会判定这是有意穿透，不再报错。

内容的提问来源于stack exchange，提问作者Fuso