no-unsafe-return

Disallow returning a value with type any from a function.

✅

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

💭

该规则需要类型信息才能运行，但这会带来性能方面的权衡。

TypeScript 中的 any 类型是来自类型系统的危险 "应急方案"。使用 any 会禁用许多类型检查规则，通常最好只作为最后的手段或在原型代码时使用。

¥The any type in TypeScript is a dangerous "escape hatch" from the type system. Using any disables many type checking rules and is generally best used only as a last resort or when prototyping code.

尽管你有最好的意图，但 any 类型有时会泄漏到你的代码库中。从函数返回 any 类型的值会在你的代码库中产生潜在的类型安全漏洞和错误来源。

¥Despite your best intentions, the any type can sometimes leak into your codebase. Returning an any-typed value from a function creates a potential type safety hole and source of bugs in your codebase.

此规则不允许从函数返回 any 或 any[]，并从异步函数返回 Promise<any>。

¥This rule disallows returning any or any[] from a function and returning Promise<any> from an async function.

此规则还比较泛型类型参数类型，以确保你不会将通用位置中的不安全 any 返回给期望特定类型的函数。例如，如果从声明为返回 Set<string> 的函数返回 Set<any>，则会出错。

¥This rule also compares generic type argument types to ensure you don't return an unsafe any in a generic position to a function that's expecting a specific type. For example, it will error if you return Set<any> from a function declared as returning Set<string>.

Flat Config
Legacy Config

eslint.config.mjs
export default tseslint.config({
  rules: {
    "@typescript-eslint/no-unsafe-return": "error"
  }
});

.eslintrc.cjs
module.exports = {
  "rules": {
    "@typescript-eslint/no-unsafe-return": "error"
  }
};

在线运行试试这个规则 ↗

示例

¥Examples

❌ Incorrect
✅ Correct

function foo1() {
  return 1 as any;
}
function foo2() {
  return Object.create(null);
}
const foo3 = () => {
  return 1 as any;
};
const foo4 = () => Object.create(null);

function foo5() {
  return [] as any[];
}
function foo6() {
  return [] as Array<any>;
}
function foo7() {
  return [] as readonly any[];
}
function foo8() {
  return [] as Readonly<any[]>;
}
const foo9 = () => {
  return [] as any[];
};
const foo10 = () => [] as any[];

const foo11 = (): string[] => [1, 2, 3] as any[];

async function foo13() {
  return Promise.resolve({} as any);
}

// generic position examples
function assignability1(): Set<string> {
  return new Set<any>([1]);
}
type TAssign = () => Set<string>;
const assignability2: TAssign = () => new Set<any>([true]);
Open in Playground

function foo1() {
  return 1;
}
function foo2() {
  return Object.create(null) as Record<string, unknown>;
}

const foo3 = () => [];
const foo4 = () => ['a'];

async function foo5() {
  return Promise.resolve(1);
}

function assignability1(): Set<string> {
  return new Set<string>(['foo']);
}
type TAssign = () => Set<string>;
const assignability2: TAssign = () => new Set(['foo']);
Open in Playground

有些情况下规则允许将 any 返回给 unknown。

¥There are cases where the rule allows to return any to unknown.

允许返回 any 到 unknown 的示例：

¥Examples of any to unknown return that are allowed:

function foo1(): unknown {
  return JSON.parse(singleObjString); // Return type for JSON.parse is any.
}

function foo2(): unknown[] {
  return [] as any[];
}
Open in Playground

选项

该规则不可配置。

何时不使用它

¥When Not To Use It

如果你的代码库有许多现有的 any 或不安全代码区域，则可能很难启用此规则。在项目不安全区域中增加类型安全性时，跳过 no-unsafe-* 规则可能会更容易。你可以考虑在这些特定情况下使用 ESLint 禁用注释，而不是完全禁用此规则。

¥If your codebase has many existing anys or areas of unsafe code, it may be difficult to enable this rule. It may be easier to skip the no-unsafe-* rules pending increasing type safety in unsafe areas of your project. You might consider using ESLint disable comments for those specific situations instead of completely disabling this rule.

示例​

选项​

何时不使用它​

相关​

示例

选项

何时不使用它

相关