noExtraNonNullAssertion

TypeScript and TSX

摘要

¥Summary

规则生效日期：v1.0.0

¥Rule available since: v1.0.0
诊断类别：lint/suspicious/noExtraNonNullAssertion

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

¥This rule is recommended, which means is enabled by default.
此规则包含 safe 修复程序。

¥This rule has a safe fix.
此规则的默认严重级别为 warning。

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

¥Sources:
- 与 @typescript-eslint/no-extra-non-null-assertion 相同
  
  ¥Same as @typescript-eslint/no-extra-non-null-assertion

如何配置

¥How to configure

1
{
2
  "linter": {
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    "rules": {
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      "suspicious": {
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        "noExtraNonNullAssertion": "error"
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      }
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    }
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  }
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}

描述

¥Description

防止在 TypeScript 文件中错误使用非空断言运算符 (!)。

¥Prevents the wrong usage of the non-null assertion operator (!) in TypeScript files.

TypeScript 中的 ! 非空断言运算符用于断言值的类型不包含 null 或 undefined。在单个值上多次使用运算符不会产生任何效果。

¥The ! non-null assertion operator in TypeScript is used to assert that a value’s type does not include null or undefined. Using the operator any more than once on a single value does nothing.

示例

¥Examples

无效

¥Invalid

1
const bar = foo!!.bar;

code-block.ts:1:13 lint/suspicious/noExtraNonNullAssertion  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Forbidden extra non-null assertion.
  
  > 1 │ const bar = foo!!.bar;
      │             ^^^^
    2 │ 
  
  ℹ Safe fix: Remove extra non-null assertion.
  
    1 │ const·bar·=·foo!!.bar;
      │                -

1
function fn(bar?: { n: number }) {
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  return bar!?.n;
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}

code-block.ts:2:10 lint/suspicious/noExtraNonNullAssertion  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Forbidden extra non-null assertion.
  
    1 │ function fn(bar?: { n: number }) {
  > 2 │   return bar!?.n;
      │          ^^^^
    3 │ }
    4 │ 
  
  ℹ Safe fix: Remove extra non-null assertion.
  
    2 │ ··return·bar!?.n;
      │             -

1
function fn(bar?: { n: number }) {
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  return ((bar!))?.();
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}

code-block.ts:2:12 lint/suspicious/noExtraNonNullAssertion  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Forbidden extra non-null assertion.
  
    1 │ function fn(bar?: { n: number }) {
  > 2 │   return ((bar!))?.();
      │            ^^^^
    3 │ }
    4 │ 
  
  ℹ Safe fix: Remove extra non-null assertion.
  
    2 │ ··return·((bar!))?.();
      │               -

有效

¥Valid

1
const bar = foo!.bar;
2

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obj?.string!.trim();
4

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function fn(key: string | null) {
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  const obj = {};
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  return obj?.[key!];
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}

noExtraNonNullAssertion

摘要

如何配置

描述

示例

无效

有效

相关链接