arrow-body-style

箭头函数体周围需要大括号

箭头函数的函数体有两种语法形式。它们可以用块体（用大括号表示）() => { ... } 或用单个表达式 () => ... 定义，其值被隐式返回。

¥Arrow functions have two syntactic forms for their function bodies. They may be defined with a block body (denoted by curly braces) () => { ... } or with a single expression () => ..., whose value is implicitly returned.

规则详情

¥Rule Details

此规则可以强制或禁止在箭头函数体周围使用大括号。

¥This rule can enforce or disallow the use of braces around arrow function body.

选项

¥Options

该规则有一个或两个选项。第一个是字符串，可以是：

¥The rule takes one or two options. The first is a string, which can be:

• "always" 在函数体周围强制使用大括号

  ¥"always" enforces braces around the function body

• "as-needed" 强制不强制可以省略大括号（默认）

  ¥"as-needed" enforces no braces where they can be omitted (default)

• "never" 强制函数体周围没有大括号（将箭头函数限制为返回表达式的角色）

  ¥"never" enforces no braces around the function body (constrains arrow functions to the role of returning an expression)

当第一个选项为 "as-needed" 时，第二个是用于更细粒度配置的对象。目前，唯一可用的选项是 requireReturnForObjectLiteral，一个布尔属性。默认为 false。如果设置为 true，它需要大括号和对象字面量的显式返回。

¥The second one is an object for more fine-grained configuration when the first option is "as-needed". Currently, the only available option is requireReturnForObjectLiteral, a boolean property. It’s false by default. If set to true, it requires braces and an explicit return for object literals.

"arrow-body-style": ["error", "always"]
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always

使用 "always" 选项的此规则的错误代码示例：

¥Examples of incorrect code for this rule with the "always" option:

/*eslint arrow-body-style: ["error", "always"]*/

let foo = () => 0;
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使用 "always" 选项的此规则的正确代码示例：

¥Examples of correct code for this rule with the "always" option:

/*eslint arrow-body-style: ["error", "always"]*/

let foo = () => {
    return 0;
};
let bar = (retv, name) => {
    retv[name] = true;
    return retv;
};
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as-needed

使用默认 "as-needed" 选项的此规则的错误代码示例：

¥Examples of incorrect code for this rule with the default "as-needed" option:

/*eslint arrow-body-style: ["error", "as-needed"]*/

let foo = () => {
    return 0;
};
let bar = () => {
    return {
       bar: {
            foo: 1,
            bar: 2,
        }
    };
};
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使用默认 "as-needed" 选项的此规则的正确代码示例：

¥Examples of correct code for this rule with the default "as-needed" option:

/*eslint arrow-body-style: ["error", "as-needed"]*/

let foo1 = () => 0;
let foo2 = (retv, name) => {
    retv[name] = true;
    return retv;
};
let foo3 = () => ({
    bar: {
        foo: 1,
        bar: 2,
    }
});
let foo4 = () => { bar(); };
let foo5 = () => {};
let foo6 = () => { /* do nothing */ };
let foo7 = () => {
    // do nothing.
};
let foo8 = () => ({ bar: 0 });
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requireReturnForObjectLiteral

此选项仅在与 "as-needed" 选项一起使用时适用。

¥This option is only applicable when used in conjunction with the "as-needed" option.

使用 { "requireReturnForObjectLiteral": true } 选项的此规则的错误代码示例：

¥Examples of incorrect code for this rule with the { "requireReturnForObjectLiteral": true } option:

/*eslint arrow-body-style: ["error", "as-needed", { "requireReturnForObjectLiteral": true }]*/

let foo = () => ({});
let bar = () => ({ bar: 0 });
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使用 { "requireReturnForObjectLiteral": true } 选项的此规则的正确代码示例：

¥Examples of correct code for this rule with the { "requireReturnForObjectLiteral": true } option:

/*eslint arrow-body-style: ["error", "as-needed", { "requireReturnForObjectLiteral": true }]*/

let foo = () => {};
let bar = () => { return { bar: 0 }; };
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never

使用 "never" 选项的此规则的错误代码示例：

¥Examples of incorrect code for this rule with the "never" option:

/*eslint arrow-body-style: ["error", "never"]*/

let foo = () => {
    return 0;
};
let bar = (retv, name) => {
    retv[name] = true;
    return retv;
};
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使用 "never" 选项的此规则的正确代码示例：

¥Examples of correct code for this rule with the "never" option:

/*eslint arrow-body-style: ["error", "never"]*/

let foo = () => 0;
let bar = () => ({ foo: 0 });
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版本

此规则是在 ESLint v1.8.0 中引入。

资源

• 规则源码
• 测试源码