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noUselessSwitchCase

诊断类别：lint/complexity/noUselessSwitchCase

¥Diagnostic Category: lint/complexity/noUselessSwitchCase

自从：v1.0.0

¥Since: v1.0.0

来源：

¥Sources:

禁止在 switch 语句中使用无用的 case。

¥Disallow useless case in switch statements.

switch 语句可以有可选的 default 子句。

¥A switch statement can optionally have a default clause.

仅当 case 子句中没有匹配项时，才会执行 default 子句。因此，位于 default 子句之前的空 case 子句是无用的。

¥The default clause will be still executed only if there is no match in the case clauses. An empty case clause that precedes the default clause is thus useless.

示例

Section titled 示例

¥Examples

无效

Section titled 无效

¥Invalid

switch (foo) {
    case 0:
    default:
        break;
    case 1:
        break;
}
code-block.js:2:5 lint/complexity/noUselessSwitchCase  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Useless case clause.
  
    1 │ switch (foo) {
  > 2 │     case 0:
      │     ^^^^^^^
    3 │     default:
    4 │         break;
  
  ℹ because the default clause is present:
  
    1 │ switch (foo) {
    2 │     case 0:
  > 3 │     default:
      │     ^^^^^^^^
  > 4 │         break;
      │         ^^^^^^
    5 │     case 1:
    6 │         break;
  
  ℹ Unsafe fix: Remove the useless case.
  
    1 1 │   switch (foo) {
    2   │ - ····case·0:
    3 2 │       default:
    4 3 │           break;
  
switch (foo) {
    default:
    case 0:
        break;
    case 1:
        break;
}
code-block.js:3:5 lint/complexity/noUselessSwitchCase  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Useless case clause.
  
    1 │ switch (foo) {
    2 │     default:
  > 3 │     case 0:
      │     ^^^^^^^
  > 4 │         break;
      │         ^^^^^^
    5 │     case 1:
    6 │         break;
  
  ℹ because the default clause is present:
  
    1 │ switch (foo) {
  > 2 │     default:
      │     ^^^^^^^^
    3 │     case 0:
    4 │         break;
  
  ℹ Unsafe fix: Remove the useless case.
  
    1 1 │   switch (foo) {
    2   │ - ····default:
    3   │ - ····case·0:
      2 │ + ····default:
    4 3 │           break;
    5 4 │       case 1:

有效

Section titled 有效

¥Valid

switch (foo) {
    case 0:
        break;
    default:
        break;
}
switch (foo) {
    case 0:
        break;
}

相关链接

Section titled 相关链接

¥Related links