no-extra-non-null-assertion

Disallow extra non-null assertions.

✅

在 ESLint 配置 中扩展"plugin:@typescript-eslint/recommended" 可启用此规则。

🔧

此规则报告的一些问题可通过 --fix ESLint 命令行选项自动修复。

TypeScript 中的 ! 非空断言运算符用于断言值的类型不包括 null 或 undefined。对单个值多次使用该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.

Flat Config

eslint.config.mjs

export default tseslint.config({
  rules: {
    "@typescript-eslint/no-extra-non-null-assertion": "error"
  }
});

Legacy Config

.eslintrc.cjs

module.exports = {
  "rules": {
    "@typescript-eslint/no-extra-non-null-assertion": "error"
  }
};

在线运行试试这个规则 ↗

示例

¥Examples

❌ Incorrect

const foo: { bar: number } | null = null;
const bar = foo!!!.bar;

Open in Playground

function foo(bar: number | undefined) {
  const bar: number = bar!!!;
}

Open in Playground

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

Open in Playground

✅ Correct

const foo: { bar: number } | null = null;
const bar = foo!.bar;

Open in Playground

function foo(bar: number | undefined) {
  const bar: number = bar!;
}

Open in Playground

function foo(bar?: { n: number }) {
  return bar?.n;
}

Open in Playground

选项

该规则不可配置。

'## 资源'

• 规则源码
• 测试源码