Develop Reference

How to programmatical import module to local scope of nodejs?

The code environment is browser. bundle tool is webpack. I have a router.js file like:
import foo from './views/foo.vue'
import bar from './views/bar.vue'
import zoo from './views/zoo.vue'
//use foo, bar, zoo variables
I've many '.vue' files to import like this under views folder. Is there a programmatical way to auto import all [name].vue as local variable [name]? So when I add or remove a vue file in views, I don't need to manually edit router.js file. this one seems a little dirty.
for (let name of ['foo', 'bar', 'zoo']) {
global[name] = require(`./views/${name}.vue`)
}

Nope, that's it. You have a choice between dynamic import and automation, or explicit coding and type-checking / linting.
Unfortunately, it's one or the other. The only other way to do it is meta-programming, where you write code to write your code.
So you generate the import statements in a loop like that, and write the string into the source file, and use delimiting comment blocks in the source file to identify and update it.

The following works for me with webpack and vue.
I actually use it for vuex and namespaces. Hope it helps you as well.
// imports all .vue files from the views folder (first parameter is the path to your views)
const requireModule = require.context('./views', false, /\.vue$/);
// create empty modules object
const modules = {};
// travers through your imports
requireModule.keys().forEach(item => {
// replace extension with nothing
const moduleName = item.replace(/(\.\/|\.vue)/g, '');
// add item to modules object
modules[moduleName] = requireModule(item).default;
});
//export modules object
export default modules;

reexport all files from a folder webpack

We're using a folder structure like this
components
| Button.js
| Nav.js
| ...etc
| index.js
somefolder
|somefile.js
in the inderx file we're importing every component and reexporting it like this
// index.js
import Button from './Button'
import Nav from './Nav'
export {Button, Nav}
this way we can import many components into a file like this
// somefile.js
import {Button, Nav} from '../components'
Maintaining that index file is a bit of a pain though and discourages flexible use of components. I know that Webpack can import many files with a syntax like this
function requireAll(r) { r.keys().forEach(r); }
requireAll(require.context('./components/', true, /\.js$/));
however, I didn't yet find a way to reexport all of these components to use them like above.
The desired outcome is to replace the index.js file with something that automates the process of bundling all the files from a folder without having to add every file manually.

I think getting rid of the file index will not be the best solution and may cause questions from other developers. But I can offer a slightly more simplified way:
index.js:
export * from './some-component1.js';
export * from './some-component2.js';
some-component1.js:
export {SomeComponent1};
some-component2.js:
export {SomeComponent2};

What does import * do in Javascript?

I was browsing through this repo on Github and was trying to comprehend the working of the code
Here, the author (or programmer) have mentioned import * at multiple places so I am trying to comprehend and understand how import * work?
First in Game.js file of his repo he have mentioned/written like this
import * as actions from '../actions';
In VS Code, when if I click on '../actions using command It is redirecting me to this file -> index.js
then in Index.js they have something like this
import * as ActionTypes from './action-types';
when I click on ./action-types it redirects me to here action-types.js
I went through firefox docs but I wasn't able to clearly make sense for the first example like for one, the action folder contains multiple files and how does import * as actions from '../actions'; mean index.js file
While i get he have called/referenced the functions using actions.functionName() or ActionType.TypeName
My Prime question remains
how does import * as actions from '../actions'; mean index.js file ?

The import * as name syntax imports all exported content of a javascript file.
For example, if you want to import an entire module's contents, then access the doAllTheAmazingThings() function
import * as myModule from '/modules/my-module.js';
myModule.doAllTheAmazingThings();
From the docs

Import in js is new syntax of ES6 to import a module it has the same work of require but its easier to filter what do you want in a module
In your example you import * as actions from '../actions'; you import all function from ../actions file
its same to do const actions = require('../actions')
but its easier to manage what you want
this syntax is not work on all browser so be sure to use transpiler with babel or other
you can see this syntax in python too

When you reference a directory in an import statement, it looks and loads the index.js file in that directory. What I usually do there is export classes and functions under that directory in a grouped object, so they can be easily accessed:
For instance in index.js I export sth like:
{
Class1,
method1
}
where each is imported as such:
import Class1 from './Class1';
So they just group the classes/methods/... that are in files in the directory.
Then you can easily access it as such:
import { Class1, method1 } from './mymodule';
vs
import Class1 from './mymodule/Class1';

In React-native Js files how can we get without folder paths is It possible?

i am developing one sample implemented Project, in this project some js files getting from paths like ./../folder/file.js and some files getting from folders like 'myfile' here second way when will we get like this.
i am confusing this second way any one clarify this .
here i am attached image please check it once image.

Suppose you have following files
app
/constants
StringConstants.js
/utils
StringHelper.js
StringConstants.js
export const DONE_BUTTON_LABEL='DONE';
export const CREATE_ALERT= 'Create Email Alert';
export const CREATE= 'CREATE';
export const CANCEL= 'Cancel';
StringHelper.js
class StringHelper {
...
}
export default new StringHelper();
How to import? See following examples
import StringHelper '../utils/StringHelper';
import * as StringConstants from '../utils/StringConstants';
//You just imported all constants from StringConstants file. Use it as StringConstants.DONE_BUTTON_LABEL or StringConstants.CREATE
import {CREATE_ALERT} StringConstants from '../utils/StringConstants';
//import CREATE_ALERT constant from StringConstants file.

ES6 modules import is undefined

I'm trying to figure out an issue I have with ES6 modules import.
This is a very simplified version of what I'm attempting to do. My current file structure is much more complicated with nested folders.
I have 2 ReactJS components:
/buttons
/MyComponent1.js
/index.js
/texts
/MyComponent2.js
/index.js
/index.js
My files look something like this:
I'm importing the MyComponent2 from the root index.js file which is the entry-point of my package.
MyComponent1.js
import MyComponent2 from '../../';
export default () => (
<div><MyComponent2 /></div>
);
MyComponent2.js
export default () => (
<div>Hello world</div>
);
My buttons/index.js and texts/index.js files export all components in their own folder:
buttons/index.js
export { default as MyComponent1 } from './MyComponent1';
texts/index.js
export { default as MyComponent2 } from './MyComponent2';
And my root index.js export all my folders to make them publicly available. It's my entry-point:
export * from './buttons';
export * from './texts';
So when I import MyComponent2 in MyComponent1 from the root index.js file, it's undefined. When I import it from ./MyComponent2.js, it's defined. When I import the entire package in another project and import MyComponent2 from the root index.js file, it's defined.
It's mind-blowing and I don't understand why I can't import MyComponent2 from the root index.js file.
I need to do that because I have a set of hundred of components nested in different folder and I want to make them all available from this entry-point file.
Can someone tell me what is happening and how to make this possible?
Thanks

Okay, took me a while to figure out what is happening. Please take a look at the sandbox i've setup - https://codesandbox.io/s/nk0qmo096j
I've tried to keep the folder/module structure similar to what you've described. Please look through how the folder/modules are structured before you continue reading.
When you run the code in the sandbox, take a look at the console. You'll see something like this -
So let me try to explain why what you're trying to do is not working
buttons/MyComponent is the first file to be "exported" (since its at the bottom of the dependency chain; Project/index -> components/index -> buttons/index -> buttons/MyComponent)
Note that components/index has not been exported yet, so it will return undefined
Then buttons/index is exported, followed by texts/index
Then buttons/MyComponent is rendered; just before it is rendered i manually require components/index and it is now defined so returns some defined value
In essence, when your MyComponent1 is trying to import MyComponent2 via the index file, the index file has not been exported yet so it returns undefined. To work around this, you have to require MyComponent2 from within MyComponent1's render method.

you can import all the components from the respective component files and then assign them to a variable in the root component and then export all of them as objects.
import MyComponent1 from './buttons/index'
import MyComponent2 from './texts/index'
export {MyComponent1, MyComponent2}
to import this components in another file or project. you could import only one them using object destructuring.
import {MyComponent1} from 'index.js'
import {MyComponent2} from 'index.js'

In my case, I had an old js file that the IDE imported instead of the updated ts file. so if your module file is module.js make sure there isn't a compiled old module.js in the same directory