语法错误：函数语句需要名称

¥Message

SyntaxError: Function statements require a function name (V8-based)
SyntaxError: function statement requires a name (Firefox)
SyntaxError: Function statements must have a name. (Safari)

¥Error type

¥What went wrong?

代码中有一个 函数语句 需要一个名字。你需要检查函数是如何定义的，以及是否需要为其提供名称，或者相关函数是否需要是函数表达式、IIFE，或者函数代码是否正确放置在此上下文中 。

¥There is a function statement in the code that requires a name. You'll need to check how functions are defined and if you need to provide a name for it, or if the function in question needs to be a function expression, an IIFE, or if the function code is placed correctly in this context at all.

¥Examples

¥Statements vs. expressions

函数语句（或函数声明）需要一个名称。这是行不通的：

¥A function statement (or function declaration) requires a name. This won't work:

function () {
  return "Hello world";
}
// SyntaxError: function statement requires a name

你可以使用 函数表达式（作业）代替：

¥You can use a function expression (assignment) instead:

const greet = function () {
  return "Hello world";
};

如果你的函数旨在成为 IIFE（立即调用函数表达式，即定义后立即运行的函数），你将需要添加更多大括号：

¥If your function is intended to be an IIFE (Immediately Invoked Function Expression, which is a function that runs as soon as it is defined) you will need to add a few more braces:

(function () {
  // …
})();

¥Labeled functions

标签 是与函数名称完全不同的特性。你不能使用标签作为函数名称。

¥Labels are an entirely different feature from function names. You can't use a label as a function name.

function Greeter() {
  german: function () {
    return "Moin";
  }
}
// SyntaxError: function statement requires a name

此外，带标签的函数声明本身也是一个已弃用的功能。请改用常规函数声明。

¥In addition, labeled function declarations themselves are a deprecated feature. Use regular function declarations instead.

function Greeter() {
  function german() {
    return "Moin";
  }
}

¥Object methods

如果你打算创建对象的方法，则需要创建一个对象。下面的 function 关键字后面没有名称的语法是有效的。

¥If you intended to create a method of an object, you will need to create an object. The following syntax without a name after the function keyword is valid then.

const greeter = {
  german: function () {
    return "Moin";
  },
};

你也可以使用 方法语法。

¥You can also use the method syntax.

const greeter = {
  german() {
    return "Moin";
  },
};

¥Callback syntax

另外，使用回调时请检查语法。大括号和逗号很快就会变得混乱。

¥Also, check your syntax when using callbacks. Braces and commas can quickly get confusing.

promise.then(
  function () {
    console.log("success");
  });
  function () {
    console.log("error");
}
// SyntaxError: function statement requires a name

正确的是：

¥Correct would be:

promise.then(
  function () {
    console.log("success");
  },
  function () {
    console.log("error");
  },
);

¥See also

• 函数 指南
• function
• function 表达
• IIFE
• 标签声明