noDuplicateElseIf

JavaScript (and super languages)

摘要

¥Summary

规则生效日期：v1.6.2

¥Rule available since: v1.6.2
诊断类别：lint/suspicious/noDuplicateElseIf

¥Diagnostic Category: lint/suspicious/noDuplicateElseIf
此规则为推荐规则，默认启用。

¥This rule is recommended, which means is enabled by default.
此规则没有修复方案。

¥This rule doesn’t have a fix.
此规则的默认严重级别为 error。

¥The default severity of this rule is error.
来源：

¥Sources:
- 与 no-dupe-else-if 相同
  
  ¥Same as no-dupe-else-if

如何配置

¥How to configure

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{
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  "linter": {
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    "rules": {
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      "suspicious": {
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        "noDuplicateElseIf": "error"
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      }
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    }
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  }
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}

描述

¥Description

禁止 if-else-if 链中的重复条件

¥Disallow duplicate conditions in if-else-if chains

当需要根据某些条件从几个可能的分支中仅执行一个分支（或最多一个分支）时，通常使用 if-else-if 链。

¥if-else-if chains are commonly used when there is a need to execute only one branch (or at most one branch) out of several possible branches, based on certain conditions.

同一链中的两个相同测试条件几乎总是代码中的错误。除非表达式中有副作用，否则重复项将评估为与链中较早的相同表达式相同的真值或假值，这意味着其分支永远无法执行。

¥Two identical test conditions in the same chain are almost always a mistake in the code. Unless there are side effects in the expressions, a duplicate will evaluate to the same true or false value as the identical expression earlier in the chain, meaning that its branch can never execute.

请注意，此规则不会将链中的条件与语句内的条件进行比较

¥Please note that this rule does not compare conditions from the chain with conditions inside statements

示例

¥Examples

无效

¥Invalid

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if (a) {
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    foo();
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} else if (b) {
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    bar();
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} else if (b) {
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    baz();
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}

code-block.js:5:12 lint/suspicious/noDuplicateElseIf ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This branch can never execute. Its condition is a duplicate or covered by previous conditions in the if-else-if chain.
  
    3 │ } else if (b) {
    4 │     bar();
  > 5 │ } else if (b) {
      │            ^
    6 │     baz();
    7 │ }

有效

¥Valid

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if (a) {
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    foo();
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} else if (b) {
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    bar();
5
} else if (c) {
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    baz();
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}

noDuplicateElseIf

摘要

如何配置

描述

示例

无效

有效

相关链接