如何从 JS 文件中导出所有函数？

Question

I'm creating a unit converter, and I want to put all of the conversion functions into their own file. Using ES6 export , is there any way to export all of the functions in the file with their default names using only one line? For example:

export default all;

The functions are all just in the file, not within an object.

Answer 1

No, there's no wildcard export (except when you're re-exporting everything from another module, but that's not what you're asking about).

Simply put export in front of each function declaration you want exported, eg

export function foo() {
    // ...
}
export function bar() {
    // ...
}

...or of course, if you're using function expressions:

export var foo = function() {
    // ...
};
export let bar = () => {
    // ...
};
export const baz = value => {
    // ...
};

Answer 2

I think there are a lot of solutions to this. And as has been answered, there's no wildcard export. But, you can 'wildcard' the import. So, I much prefer the one putting export before each of the functions you want to expose from the file:

//myfile.js
export function fn1() {...} 
export function fn2() {...}

and then import it like so:

import * as MyFn from './myfile.js'

Afterwards you could use it like so:

MyFn.fn1();
MyFn.fn2();

Answer 3

You can also use module.exports as follows:

function myFunction(arg) {
  console.debug(arg);
}
function otherFunction(arg) {
  console.error(arg);
}

module.exports = {
  myFunction: myFunction,
  otherFunction: otherFunction,
};

Then you can import it:

import {myFunction, otherFunction} from "./Functions.js";

Answer 4

Regarding my use case, I do have three reusable functions in one file.

utils/reusables.js

export const a = () => {}
export const b = () => {}
export const c = () => {}

In order to point the root folder instead of individual file names, I created a file called index.js which will comprise of all the functions that are listed in individual files.

utils/index.js

export * from './reusables'

Now, when I want to use my a function, I will have to simply import it like this

import { a } from '../utils'

Rather than calling it from its individual files

import { a } from '../utils/reusables'

Answer 5

You could also export them at the bottom of your script.

function cube(x) {
  return x * x * x;
}

const foo = Math.PI + Math.SQRT2;

var graph = {
  options: {
      color:'white',
      thickness:'2px'
  },
  draw: function() {
      console.log('From graph draw function');
  }
}

export { cube, foo, graph };

You can also aggregate submodules together in a parent module so that they are available to import from that module.

// In parentModule.js
export { myFunction, myVariable } from 'childModule1.js';
export { myClass } from 'childModule2.js';

// In top-level module
import { myFunction, myVariable, myClass } from 'parentModule.js'

Answer 6

For Node.js environment, what I did to export functions was this.

UserController.js

module.exports = {
  signUp: () => {
    return "user"
  },
  login: () => {
    return "login"
  }
}

UserRouter.js

const UserController = require('./UserController')

then login and signUp functions could be used inside UserRouter as UserController.signUp() and UserController.login()

Answer 7

I think there's a missing common solution, which is exporting in index.js file:

myModule/myFunctions.js

export const foo = () => { ... }
export const bar = () => { ... }

then in myModule/index.js

export * from "./myFunctions.js";

This way you can simply import and use it with:

import { foo, bar } from "myModule";
foo();
bar();

Answer 8

functions.js

function alpha(msj) {
    console.log('In alpha: ' + msj);
}

function beta(msj) {
    console.log('In beta: ' + msj);
}

module.exports = {
    alpha,
    beta
};

main.js

const functions = require('./functions');
functions.alpha('Hi');
functions.beta('Hello');

Run

node main.js

Output

In alpha: Hi
In beta: Hello

Answer 9

In case anyone still needs an answer to this in modern JavaScript:

const hello = () => "hello there"
const bye = () => "bye bye"
export default { hello, bye }