ES6 exporting/importing in index file - javascript

I am currently using ES6 in an React app via webpack/babel.
I am using index files to gather all components of a module and export them. Unfortunately, that looks like this:
import Comp1_ from './Comp1.jsx';
import Comp2_ from './Comp2.jsx';
import Comp3_ from './Comp3.jsx';
export const Comp1 = Comp1_;
export const Comp2 = Comp2_;
export const Comp3 = Comp3_;
So I can nicely import it from other places like this:
import { Comp1, Comp2, Comp3 } from './components';
Obviously that isn't a very nice solution, so I was wondering, if there was any other way. I don't seem to able to export the imported component directly.

You can easily re-export the default import:
export {default as Comp1} from './Comp1.jsx';
export {default as Comp2} from './Comp2.jsx';
export {default as Comp3} from './Comp3.jsx';
There also is a proposal for ES7 ES8 that will let you write export Comp1 from '…';.

Also, bear in mind that if you need to export multiple functions at once, like actions you can use
export * from './XThingActions';

Too late but I want to share the way that I resolve it.
Having model file which has two named export:
export { Schema, Model };
and having controller file which has the default export:
export default Controller;
I exposed in the index file in this way:
import { Schema, Model } from './model';
import Controller from './controller';
export { Schema, Model, Controller };
and assuming that I want import all of them:
import { Schema, Model, Controller } from '../../path/';

default export
// Default export (recommended)
export {default} from './module'
// Default export with alias
export {default as d1} from './module'
all export
// In >ES7, it could be
export * from './module'
// In >ES7, with alias
export * as d1 from './module'
function name export
// export by function names
export { funcName1, funcName2, …} from './module'
// export by aliases
export { funcName1 as f1, funcName2 as f2, …} from './module'
destructured object export
// export destructured object
export const { myVar, myFunction } = myObjectWithEverything
// export destructured object, with renaming
export const { v1: myVar, f1: myFunction } = myBigObject
with array
// it works with array as well
export const [ funcName1, funcName2 ] = myBigArray
More infos: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/export

Folder structure:
components|
|_ Nave.js
|_Another.js
|_index.js
Nav.js comp inside components folder
export {Nav}
index.js in component folder
export {Nav} from './Nav';
export {Another} from './Another';
import anywhere
import {Nav, Another} from './components'

I've been searching for years how to export modules as both, named exports, and default exports in modular JavaScript. After tons of experimenting, the solution I found is quite simple and efficient.
// index.js
export { default as Client } from "./client/Client.js";
export { default as Events } from "./utils/Events.js";
// Or export named exports
export { Client } from "./client/Client.js";
export { Events } from "./utils/Events.js";
export * as default from "./index.js";
This would allow each exported module to be imported in two ways:
// script.js
import { Client } from "index.js";
new Client();
import module from "index.js";
new module.Client();
// You could also do this if you prefer to do so:
const { Client } = module;
You can mess around with this to have it suit your needs, but it works for me. Hope it helps!

What worked for me was adding the type keyword:
export type { Comp1, Comp2 } from './somewhere';

Install #babel/plugin-proposal-export-default-from via:
yarn add -D #babel/plugin-proposal-export-default-from
In your .babelrc.json or any of the Configuration File Types
module.exports = {
//...
plugins: [
'#babel/plugin-proposal-export-default-from'
]
//...
}
Now you can export directly from a file-path:
export Foo from './components/Foo'
export Bar from './components/Bar'
Good Luck...

Related

How to export multiple components

I have a shared folder that I expose as an npm module.
inside that share folder I have a components folder with index.js that exports them as default:
export { default as AqMegaMenu } from "./megaMenu/AqMegaMenu.vue";
export { default as AqDetailsCard } from "./AqDetailsCard.vue";
export { default as AqDoughnutChart } from "./charts/AqDoughnutChart.vue";
...
My entry file for the library is main.js and i'd like to expose my entire components through it, so I import them in other projects like this:
import {Comp1, Comp2} from "#my/shared"
Currently I export them one by one in main.js:
export { default as AqDetailsCard } from "./components/AqDetailsCard.vue";
...
But i was wondering if there is a way to export the entire components directory using it's index.js
and still be able to import it in other projects like i showed above.
You may try something like this
import camelCase from 'lodash/camelCase'
const requireModule = require.context('./components', true, /\.vue$/)
const modules = {}
requireModule.keys().forEach(filename =>
{
const moduleName = camelCase(fileName.match(/([^\\\/]+)\.vue$/)[1]);
modules[moduleName] = requireModule(fileName)
})
export default modules

How to Export Variables with a Dynamic Names

I have a components folder in nuxt.js
/components/atoms/
and inside that folder I have an index.js to export all components dynamically
const req = require.context('./', true, /\.vue$/)
const components = {}
req.keys().forEach(fileName => {
const componentName = fileName.replace(/^.+\/([^/]+)\.vue/, '$1')
components[componentName] = req(fileName).default
})
export const { ButtonStyled, TextLead, InputSearch } = components
so I can import perfectly as I wish
import { ButtonStyled } from "#/components/atoms"
the problem is that I am defining the variables to be exported statically, fixed, so for each created component I would need to add another variable manually
I need to dynamically export the variable name
Example:
DynamicCreation = ['ButtonStyled', 'TextLead', 'InputSearch']
export const { DynamicCreation } = components
// output -> export const { ButtonStyled, TextLead,InputSearch } = components
I need to export the name of already unstructured variables
Note: I can not use this export default components because I can not import like this import { ButtonStyled } from "#/components/atoms"
You should be able to do it like this:
export default components
Then in your file where you want to use the components:
import * as components from '#/components/atoms'
Then when you need to use the components in your Vue files, you need to map them:
#Component({
components: {
ButtonStyled: components.ButtonStyled
}
})
And now you have:
<ButtonStyled></ButtonStyled>
You can make something like this way, check if is what do you need.
Create a file to import a conjunct of components: allComponents.js
export default {
componentOne: require('./passToOneComponent.js');
componentTwo: require('./passToOneComponent.js');
componentThree: require('./passToOneComponent.js');
}
After in index.js export the allComponents.js with the name that you wish:
export {default as SomeName } from 'allComponents.js';
So in the final file, you can make something like:
import { SomeName } from 'index.js';
SomeName.componentOne();
I created a library that does this type of export, anyone who wants can install via npm
I created a Webpack Plugin that makes named exports from a component, maybe this helps other people
Weback Plugin - named-exports

how to import Helper class in react

I am creating a helper class in react. The image below shows my setup:
In my App.js, I have:
import Helpers from './Helpers.js'
I have also tried:
import Helpers from './components/Helpers.js'
import Helpers from 'src/components/Helpers.js'
import Helpers from './components/Helpers.js'
import Helpers from 'src/components/Helpers.js'
import {Helpers} from './components/Helpers.js'
import {Helpers} from 'src/components/Helpers.js'
and I have also tried, in my Helpers.js:
export default Helpers
export default Helpers();
However, I receive an error message:
'./Helpers.js' does not contain an export named 'Helpers'.
It seems as though App.js can not find and locate this class. How can I import it, so i can just call the functions, like:
Helpers.helperFunctionHere();
thanks.
Option 1: Export each function individually
In Helpers.js
export function helperFunctionHere() {
console.log("hello there");
}
In App.js
import {helperFunctionHere} from "./Helpers";
render() {
helperFunctionHere();
}
Option 2: Static properties on the class
In Helpers.js
class Helpers {
static helperFunctionHere() {
console.log("hi");
}
}
export default Helpers
In App.js
import Helpers from "./Helpers";
render() {
Helpers.helperFunctionHere();
}
Should be export default Helpers. Am also assuming that your bundler is setup correctly.

ES6 how to export all item from one file

I want to export all methods of a file from another file.
currently I am doing this, and it works. How can I merge below two into 1 export expression
import * as db from './web/query';
export default db;
I tried below written 1 line exports but all failed
export * from './web/query'; //==error
export * as default from './web/query'; //==error
export * as {default} from './web/query'; //==error
export from from './web/query'; //== error
export default from './web/query'; //== error
Error means
import db from '../db/index';
db is undefined here. However the the first methods works
Inside of file './web/query' looks like
export function foo(){}
export function baar(){}
You cannot in ES2016. To create a module namespace object, you need to give it an identifier (like db) in your current module scope, and then re-export that. There's no way around it.
There is however a stage 1 proposal to add the export * as default from … syntax you were trying.
How can I merge below two into 1 export expression
You cannot.
ES2015 (and ES2016) does not provide a syntax that would allow you to import all the named exports from a file and export the object (with those as its properties) as default in a single statement.
You can export the named exports of another file with export * from '<FILE>';.
// a.js
export const one = '1';
export const two = '2';
// b.js
export * from './a.js';
// c.js
import { one, two } from './b.js';
you can do something like this:
a.js:
const fakeName = "Blabla";
const fakeAge = 33;
module.exports = {fakeName, fakeAge}
b.js:
const name = "Someone";
let age = 22;
module.exports = { name, age}
c.mjs:
export * from './a.js';
export * from './b.js';
index.mjs:
import * as AllClass from './c.mjs'
export default AllClass
use it in e.g server.mjs:
import AllClass from './index.mjs'
console.log("fakeName:", AllClass.fakeName);
console.log("NAME:",AllClass.name);
It's just hard not to get confused with ESModule imports/exports and CommonJS imports and exports...

ES6 import all files in a folder? [duplicate]

With ES6, I can import several exports from a file like this:
import {ThingA, ThingB, ThingC} from 'lib/things';
However, I like the organization of having one module per file. I end up with imports like this:
import ThingA from 'lib/things/ThingA';
import ThingB from 'lib/things/ThingB';
import ThingC from 'lib/things/ThingC';
I would love to be able to do this:
import {ThingA, ThingB, ThingC} from 'lib/things/*';
or something similar, with the understood convention that each file contains one default export, and each module is named the same as its file.
Is this possible?
I don't think this is possible, but afaik the resolution of module names is up to module loaders so there might a loader implementation that does support this.
Until then, you could use an intermediate "module file" at lib/things/index.js that just contains
export * from 'ThingA';
export * from 'ThingB';
export * from 'ThingC';
and it would allow you to do
import {ThingA, ThingB, ThingC} from 'lib/things';
Just a variation on the theme already provided in the answer, but how about this:
In a Thing,
export default function ThingA () {}
In things/index.js,
export {default as ThingA} from './ThingA'
export {default as ThingB} from './ThingB'
export {default as ThingC} from './ThingC'
Then to consume all the things elsewhere,
import * as things from './things'
things.ThingA()
Or to consume just some of things,
import {ThingA,ThingB} from './things'
The current answers suggest a workaround but it's bugged me why this doesn't exist, so I've created a babel plugin which does this.
Install it using:
npm i --save-dev babel-plugin-wildcard
then add it to your .babelrc with:
{
"plugins": ["wildcard"]
}
see the repo for detailed install info
This allows you to do this:
import * as Things from './lib/things';
// Do whatever you want with these :D
Things.ThingA;
Things.ThingB;
Things.ThingC;
again, the repo contains further information on what exactly it does, but doing it this way avoids creating index.js files and also happens at compile-time to avoid doing readdirs at runtime.
Also with a newer version you can do exactly like your example:
import { ThingsA, ThingsB, ThingsC } from './lib/things/*';
works the same as the above.
You now can use async import():
import fs = require('fs');
and then:
fs.readdir('./someDir', (err, files) => {
files.forEach(file => {
const module = import('./' + file).then(m =>
m.callSomeMethod();
);
// or const module = await import('file')
});
});
Great gugly muglys! This was harder than it needed to be.
Export one flat default
This is a great opportunity to use spread (... in { ...Matters, ...Contacts } below:
// imports/collections/Matters.js
export default { // default export
hello: 'World',
something: 'important',
};
// imports/collections/Contacts.js
export default { // default export
hello: 'Moon',
email: 'hello#example.com',
};
// imports/collections/index.js
import Matters from './Matters'; // import default export as var 'Matters'
import Contacts from './Contacts';
export default { // default export
...Matters, // spread Matters, overwriting previous properties
...Contacts, // spread Contacts, overwriting previosu properties
};
// imports/test.js
import collections from './collections'; // import default export as 'collections'
console.log(collections);
Then, to run babel compiled code from the command line (from project root /):
$ npm install --save-dev #babel/core #babel/cli #babel/preset-env #babel/node
(trimmed)
$ npx babel-node --presets #babel/preset-env imports/test.js
{ hello: 'Moon',
something: 'important',
email: 'hello#example.com' }
Export one tree-like default
If you'd prefer to not overwrite properties, change:
// imports/collections/index.js
import Matters from './Matters'; // import default as 'Matters'
import Contacts from './Contacts';
export default { // export default
Matters,
Contacts,
};
And the output will be:
$ npx babel-node --presets #babel/preset-env imports/test.js
{ Matters: { hello: 'World', something: 'important' },
Contacts: { hello: 'Moon', email: 'hello#example.com' } }
Export multiple named exports w/ no default
If you're dedicated to DRY, the syntax on the imports changes as well:
// imports/collections/index.js
// export default as named export 'Matters'
export { default as Matters } from './Matters';
export { default as Contacts } from './Contacts';
This creates 2 named exports w/ no default export. Then change:
// imports/test.js
import { Matters, Contacts } from './collections';
console.log(Matters, Contacts);
And the output:
$ npx babel-node --presets #babel/preset-env imports/test.js
{ hello: 'World', something: 'important' } { hello: 'Moon', email: 'hello#example.com' }
Import all named exports
// imports/collections/index.js
// export default as named export 'Matters'
export { default as Matters } from './Matters';
export { default as Contacts } from './Contacts';
// imports/test.js
// Import all named exports as 'collections'
import * as collections from './collections';
console.log(collections); // interesting output
console.log(collections.Matters, collections.Contacts);
Notice the destructuring import { Matters, Contacts } from './collections'; in the previous example.
$ npx babel-node --presets #babel/preset-env imports/test.js
{ Matters: [Getter], Contacts: [Getter] }
{ hello: 'World', something: 'important' } { hello: 'Moon', email: 'hello#example.com' }
In practice
Given these source files:
/myLib/thingA.js
/myLib/thingB.js
/myLib/thingC.js
Creating a /myLib/index.js to bundle up all the files defeats the purpose of import/export. It would be easier to make everything global in the first place, than to make everything global via import/export via index.js "wrapper files".
If you want a particular file, import thingA from './myLib/thingA'; in your own projects.
Creating a "wrapper file" with exports for the module only makes sense if you're packaging for npm or on a multi-year multi-team project.
Made it this far? See the docs for more details.
Also, yay for Stackoverflow finally supporting three `s as code fence markup.
Similar to the accepted answer but it allows you to scale without the need of adding a new module to the index file each time you create one:
./modules/moduleA.js
export const example = 'example';
export const anotherExample = 'anotherExample';
./modules/index.js
// require all modules on the path and with the pattern defined
const req = require.context('./', true, /.js$/);
const modules = req.keys().map(req);
// export all modules
module.exports = modules;
./example.js
import { example, anotherExample } from './modules'
If you are using webpack. This imports files automatically and exports as api namespace.
So no need to update on every file addition.
import camelCase from "lodash-es";
const requireModule = require.context("./", false, /\.js$/); //
const api = {};
requireModule.keys().forEach(fileName => {
if (fileName === "./index.js") return;
const moduleName = camelCase(fileName.replace(/(\.\/|\.js)/g, ""));
api[moduleName] = {
...requireModule(fileName).default
};
});
export default api;
For Typescript users;
import { camelCase } from "lodash-es"
const requireModule = require.context("./folderName", false, /\.ts$/)
interface LooseObject {
[key: string]: any
}
const api: LooseObject = {}
requireModule.keys().forEach(fileName => {
if (fileName === "./index.ts") return
const moduleName = camelCase(fileName.replace(/(\.\/|\.ts)/g, ""))
api[moduleName] = {
...requireModule(fileName).default,
}
})
export default api
I've used them a few times (in particular for building massive objects splitting the data over many files (e.g. AST nodes)), in order to build them I made a tiny script (which I've just added to npm so everyone else can use it).
Usage (currently you'll need to use babel to use the export file):
$ npm install -g folder-module
$ folder-module my-cool-module/
Generates a file containing:
export {default as foo} from "./module/foo.js"
export {default as default} from "./module/default.js"
export {default as bar} from "./module/bar.js"
...etc
Then you can just consume the file:
import * as myCoolModule from "my-cool-module.js"
myCoolModule.foo()
Just an other approach to #Bergi's answer
// lib/things/index.js
import ThingA from './ThingA';
import ThingB from './ThingB';
import ThingC from './ThingC';
export default {
ThingA,
ThingB,
ThingC
}
Uses
import {ThingA, ThingB, ThingC} from './lib/things';
Nodejs ? Do like this:
Create a folder with index.js, in index file, add this:
var GET = require('./GET');
var IS = require('./IS');
var PARSE = require('./PARSE');
module.exports = { ...GET, ...IS, ...PARSE};
And, in file GET.js, or IS.js export as normal:
module.exports = { /* something as you like */}
ANd now, you need only including index.js like:
const Helper = require('./YourFolder');
Helper will include all of function in YourFolder.
Good day!
This is not exactly what you asked for but, with this method I can Iterate throught componentsList in my other files and use function such as componentsList.map(...) which I find pretty usefull !
import StepOne from './StepOne';
import StepTwo from './StepTwo';
import StepThree from './StepThree';
import StepFour from './StepFour';
import StepFive from './StepFive';
import StepSix from './StepSix';
import StepSeven from './StepSeven';
import StepEight from './StepEight';
const componentsList= () => [
{ component: StepOne(), key: 'step1' },
{ component: StepTwo(), key: 'step2' },
{ component: StepThree(), key: 'step3' },
{ component: StepFour(), key: 'step4' },
{ component: StepFive(), key: 'step5' },
{ component: StepSix(), key: 'step6' },
{ component: StepSeven(), key: 'step7' },
{ component: StepEight(), key: 'step8' }
];
export default componentsList;
You can use require as well:
const moduleHolder = []
function loadModules(path) {
let stat = fs.lstatSync(path)
if (stat.isDirectory()) {
// we have a directory: do a tree walk
const files = fs.readdirSync(path)
let f,
l = files.length
for (var i = 0; i < l; i++) {
f = pathModule.join(path, files[i])
loadModules(f)
}
} else {
// we have a file: load it
var controller = require(path)
moduleHolder.push(controller)
}
}
Then use your moduleHolder with dynamically loaded controllers:
loadModules(DIR)
for (const controller of moduleHolder) {
controller(app, db)
}
I was able to take from user atilkan's approach and modify it a bit:
For Typescript users;
require.context('#/folder/with/modules', false, /\.ts$/).keys().forEach((fileName => {
import('#/folder/with/modules' + fileName).then((mod) => {
(window as any)[fileName] = mod[fileName];
const module = new (window as any)[fileName]();
// use module
});
}));
if you don't export default in A, B, C but just export {} then it's possible to do so
// things/A.js
export function A() {}
// things/B.js
export function B() {}
// things/C.js
export function C() {}
// foo.js
import * as Foo from ./thing
Foo.A()
Foo.B()
Foo.C()

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