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prefer-return-this-type

Enforce that this is used when only this type is returned.

🔒

在 ESLint 配置 中扩展"plugin:@typescript-eslint/strict-type-checked" 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。

💭

该规则需要 类型信息 才能运行。


方法链接 是 OOP 语言中的常见模式，TypeScript 提供了一个特殊的 多态性 this 型 来促进它。 显式声明类名的返回类型而不是 this 的类方法使得扩展类调用该方法变得更加困难： 返回的对象将被键入为基类，而不是派生类。

英：Method chaining is a common pattern in OOP languages and TypeScript provides a special polymorphic this type to facilitate it. Class methods that explicitly declare a return type of the class name instead of this make it harder for extending classes to call that method: the returned object will be typed as the base class, not the derived class.

此规则报告类方法何时声明该类名而不是 this 的返回类型。

英：This rule reports when a class method declares a return type of that class name instead of this.

class Animal {
  eat(): Animal {
    //   ~~~~~~
    // Either removing this type annotation or replacing
    // it with `this` would remove the type error below.
    console.log("I'm moving!");
    return this;
  }
}

class Cat extends Animal {
  meow(): Cat {
    console.log('Meow~');
    return this;
  }
}

const cat = new Cat();
cat.eat().meow();
//        ~~~~
// Error: Property 'meow' does not exist on type 'Animal'.
// because `eat` returns `Animal` and not all animals meow.
.eslintrc.cjs
module.exports = {
  "rules": {
    "@typescript-eslint/prefer-return-this-type": "error"
  }
};
在线运行试试这个规则 ↗

示例​

class Foo {
  f1(): Foo {
    return this;
  }
  f2 = (): Foo => {
    return this;
  };
  f3(): Foo | undefined {
    return Math.random() > 0.5 ? this : undefined;
  }
}
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何时不使用它​

如果你不使用方法链接或显式返回值，则可以安全地关闭此规则。

英：If you don't use method chaining or explicit return values, you can safely turn this rule off.

选项​

该规则不可配置。

资源​