CODEWITHSUNDEEP
javascript
Laser
Laser

Reputation: 5439

What does the @ symbol do in javascript imports?

For example: 

import Component from '@/components/component'

In the code I'm looking at it behaves like ../ going up one level in the directory relative to the file path, but I'd like to know more generally what it does. Unfortunately I can't find any documentation online due to the symbol searching problem.

Upvotes: 351

Views: 118144

Answers (8)

Can Rau
Can Rau

Reputation: 3819

Know it's old, but I wasn't exactly sure how it's defined, so looked it up, came by, dug a little deeper and finally found this in my Vue-CLI (Vue.js) generated Webpack config

resolve: {
    extensions: ['.js', '.vue', '.json'],
    alias: {
    '@': path.join(__dirname, '..', dir)
    }
},

so it's an alias which in this case points to the root of vue-cli generated src directory of the project

Update: As correctly mentioned by @aderchox in the comments, this is a general Webpack feature and not limited to Vue

Upvotes: 153

Daniel Hua
Daniel Hua

Reputation: 305

I am using VS code to build react native Apps.

What you need is:

  1. create a jsconfig.json under root path of your App enter image description here
  1. in your jsconfig.json, add the following code:
{
  "compilerOptions": {
    "baseUrl": ".",
    "target": "ES6",
    "module": "commonjs",
    "paths": {
      "@/*": ["src/*"],
      "@components/*": ["src/components/*"],
      "@core/*": ["src/core/*"]
    }
  },
  "exclude": ["node_modules"]
}

basically like "shortcut" : ["abs_path"]

Upvotes: 15

Johnny Kontrolletti
Johnny Kontrolletti

Reputation: 899

In case you are using Typescript, you could achieve this by simply using your tsconfig.json like this:

{
  "compilerOptions": {

    ...

    "baseUrl": ".",
    "paths": {
      "@lib/*": ["app/lib/*"]
    }
  },
}

Upvotes: 14

John
John

Reputation: 6668

// @ is an alias to /src

Inspired by Can Rau's answer I made a similar discovery in my src/views/Home.vue file. This file was created with the latest (July 2021, Ubuntu 20.04) versions: npx @vue/cli create myfirstvue --default.

I "inferred" it was /src but wanted to know why, because Ben's accepted answer said it would be the root of my project, which in fact is the parent, of /src.

Here is Home.vue:

...
<script>
// @ is an alias to /src
import HelloWorld from '@/components/HelloWorld.vue'
</script>

It is defined by Vue Webpack template, which I learned from this other SO answer.

Upvotes: 2

mabreu0
mabreu0

Reputation: 90

It is a way of remapping module paths, not part of the ES itself, you have to use babel import feature.

Upvotes: 1

Ali MasudianPour
Ali MasudianPour

Reputation: 14459

To make Ben's answer more comprehensive:

First you need to add babel-plugin-root-import in your devDependencies in package.json (If using yarn: yarn add babel-plugin-root-import --dev). Then in your .babelrc add the following lines into plugins key:

"plugins": [
[
  "babel-plugin-root-import",
  {
    "rootPathPrefix": "@"
  }
]
]

Now, you can use @. For example:

Instead of

import xx from '../../utils/somefile'

You Can

import xx from '@/utils/somefile'

Upvotes: 46

Wale
Wale

Reputation: 1393

As said above, this feature is not in JS by default. You have to use a babel plugin to enjoy it. And its job is simple. It allows you to specify a default root source for your JS files and helps you map your file imports to it. To get started install through either npm:

npm install babel-plugin-root-import --save-dev

or

yarn add babel-plugin-root-import --dev

Create a .babelrc in the root of your app and configure these settings to your taste:

{
  "plugins": [
    ["babel-plugin-root-import", {
      "rootPathSuffix": "the-preferred/root/of-all-your/js/files",
      "rootPathPrefix": "@"
    }]
  ]
}

With the config above, you can simply import from that source like:

import Myfile from "@/Myfile"

without doing all this funky stuff:

"/../../../Myfile"

Note that you can also change the symbol to anything like "~" if that floats your boat.

Upvotes: 20

Ben
Ben

Reputation: 21249

The meaning and structure of the module identifier depends on the module loader or module bundler. The module loader is not part of the ECMAScript spec. From a JavaScript language perspective, the module identifier is completely opaque. So it really depends on which module loader/bundler you are using.

You most likely have something like babel-plugin-root-import in your webpack/babel config.

Basically it means from the root of the project.. it avoids having to write things like import Component from '../../../../components/component'

Edit: One reason it exists is because import Component from 'components/component' doesn't do that but instead search in the node_modules folder

Upvotes: 293

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