react error unexpected default export of anonymous function-ag捕鱼王app官网

current location：home > learning > web front-end > react >

vue react javascript angular css html

react error unexpected default export of anonymous function

author：jiyik last updated：2025/03/07 views：

the "unexpected default export of anonymous function" warning is caused when we try to export an anonymous function using default export. to fix the error, name the function before exporting it.

the following is a sample code that produces the above error

header.js

// 👇️ default export for anonymous function

// ⛔️ unexpected default export of anonymous function
// eslint import/no-anonymous-default-export
export default function () {
  return <h1>hello worldh1>;
}

the problem here is that we are using default export to export the anonymous function.

to fix the error, name the function before using the default export.

header.js

// 👇️ give name to function that's being exported
export default functionheader() {
  return <h1>hello worldh1>;
}

important: if we export a variable (or arrow function) as a default export, we must declare it on the first line and export it on the next line. we cannot declare and default export a variable on the same line.

header.js

const header = () => {
  return <h1>hello worldh1>;
};

export default header;

now we can still import functions using default import.

app.js

import header from './header';

const app = () => (
  <div><header />div>
);

export default app;

this approach encourages reusing the same identifiers when exporting and importing functions.

by default, eslint rules will warn us about anonymous default exports of all types, such as arrays, functions, classes, objects, etc.

if you want to disable a single line rule, you can use comment.

header.js

// eslint-disable-next-line import/no-anonymous-default-export
export default function () {
  return <h1>hello worldh1>;
}

the comment should be placed just above the code with the anonymous default export.

optionally, we can update what import/no-anonymous-default-exportthe rule should .eslintrccheck for in the file.

the options section of the github repository shows the full default configuration for the rule, which we can .eslintrctweak in the rule object in our ./configure file.

summarize

the "unexpected default export of anonymous function" warning is caused when we try to export an anonymous function using default export. to fix the error, name the function before exporting it.

previous：ref returns undefined or null in react

next: none

for reprinting, please send an email to 1244347461@qq.com for approval. after obtaining the author's consent, kindly include the source as a link.

article url：

ref returns undefined or null in react

publish date：2025/03/07 views：112 category：react

当我们在呈现相应的 dom 元素之前尝试访问其当前属性时，react ref 最常返回 undefined 或 null 。要解决此问题，需要在 useeffect 钩子中或在触发事件时访问 ref。 import {useref, useeffect} from

passing boolean values as props to components in react

publish date：2025/03/07 views：112 category：react

要将布尔值作为 props 传递给 react 中的组件，请将布尔值包裹在花括号中，例如 child bool={true} / 。我们传递给组件的所有非字符串类型的道具都必须用大括号括起来。 function child ( {bo

using ref to get the height of an element in react

publish date：2025/03/07 views：195 category：react

在 react 中使用 ref 获取元素的高度：初始化将存储元素高度的状态变量。在 useeffect() 挂钩中更新元素的高度。高度应设置为 ref.current.clientheight 。 import {useeffect, usestate, useref} from re

publish date：2025/03/07 views：133 category：react

在 react 中使用 ref 改变元素的样式：在元素上设置 ref 属性。通过 ref 上的 current 属性访问元素。更新元素的样式，例如 ref.current.style.backgroundcolor = green 。 import {useref} from react ; cons

setting and accessing state with dynamic keys in react

publish date：2025/03/07 views：67 category：react

使用方括号表示法在 react 中使用动态键设置和访问状态，例如 setemployee({...employee, [key]: employee.salary 100}) 。方括号中的变量或表达式将在设置状态之前进行评估。 import {usestate} from

add an event listener to the body element in react

publish date：2025/03/07 views：131 category：react

向 body 元素添加事件监听器：访问文档对象上的 body 元素。在 useeffect 钩子中对 body 元素使用 addeventlistener() 方法。当组件卸载时移除事件侦听器。 import {useeffect} from react ; export defa

check if an element is in the viewport in react.js

publish date：2025/03/07 views：89 category：react

在 react.js 中检查元素是否在 viewport 中：在元素上设置 ref 属性。使用 intersectionobserver api 来跟踪元素是否相交。 app.js import {useeffect, useref, usestate, usememo} from react ; export default function

publish date：2025/03/07 views：161 category：react

要在 react 中按下 enter 键时获取输入的值：在输入字段上设置 onkeydown 属性。当用户按下一个键时，检查该键是否为 enter 。从状态变量访问输入字段的值。 import {usestate} from react ; co

publish date：2025/03/06 views：154 category：react

要使用钩子清除 react 中的 timeout 或 interval：使用 useeffect 钩子设置超时或间隔。从 useeffect 钩子返回一个函数。使用 cleartimeout() 或 clearinterval() 方法删除组件卸载时的超时。、 import

react error unexpected default export of anonymous function-ag捕鱼王app官网