The Typescript support is not added by default to your project (unless you selected TS when you created your project folder), but it can be easily integrated by following the guide on this page.
TIP
The following steps are only required when you have not selected TypeScript support when creating a fresh Quasar project. If you selected the TS option on project creation, TypeScript support is already enabled.
Installation of TypeScript Support
In order to support TypeScript, you’ll need to change the extension of your quasar.config file: /quasar.config file:
import { configure } from "quasar/wrappers";
module.exports = configure((ctx) => {
return {
supportTS: true,
// ...
}
});Then create /tsconfig.json file at the root of you project with this content:
{
"extends": "@quasar/app-webpack/tsconfig-preset",
"compilerOptions": {
"baseUrl": "."
},
"exclude": [
"./dist",
"./.quasar",
"./node_modules",
"./src-capacitor",
"./src-cordova",
"./quasar.config.*.temporary.compiled*"
]
}Now you can start using TypeScript into your project.
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Remember that you must change the extension of your JavaScript files to .ts to be allowed to write TypeScript code inside them. To write TS code into your components, instead, change the script opening tag like so <script lang="ts">.
WARNING
If you fail to add the tsconfig.json file, the application will break at compile time!
Handling TS Webpack loaders @quasar/app-webpack =v3
Behind the curtains, Quasar uses ts-loader and fork-ts-checker-webpack-plugin (provided by @quasar/app-webpack package) to manage TS files. If you ever need to provide a custom configuration for these libs you can do so by making build property like so:
module.exports = function (ctx) {
return {
supportTS: {
tsLoaderConfig: {
// `appendTsSuffixTo: [/\.vue$/]` and `transpileOnly: true` are added by default and cannot be overridden
...
},
tsCheckerConfig: {
// `vue: true` is added by default and cannot be overridden
...
}
},
....
}
}Linting setup
First add the needed dependencies:
$ yarn add --dev eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin
# you might also want to install the `eslint-plugin-vue` package.Then update your ESLint configuration accordingly, like in the following example:
const { resolve } = require('node:path');
module.exports = {
// https://eslint.org/docs/user-guide/configuring#configuration-cascading-and-hierarchy
// This option interrupts the configuration hierarchy at this file
// Remove this if you have an higher level ESLint config file (it usually happens into a monorepos)
root: true,
// https://eslint.vuejs.org/user-guide/#how-to-use-custom-parser
// Must use parserOptions instead of "parser" to allow vue-eslint-parser to keep working
// `parser: 'vue-eslint-parser'` is already included with any 'plugin:vue/**' config and should be omitted
parserOptions: {
// https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/parser#configuration
// https://github.com/TypeStrong/fork-ts-checker-webpack-plugin#eslint
// Needed to make the parser take into account 'vue' files
extraFileExtensions: ['.vue'],
parser: '@typescript-eslint/parser',
project: resolve(__dirname, './tsconfig.json'),
tsconfigRootDir: __dirname,
ecmaVersion: 2021, // Allows for the parsing of modern ECMAScript features
sourceType: 'module', // Allows for the use of imports
},
// Rules order is important, please avoid shuffling them
extends: [
// Base ESLint recommended rules
'eslint:recommended',
// https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/eslint-plugin#usage
// ESLint typescript rules
'plugin:@typescript-eslint/eslint-recommended',
'plugin:@typescript-eslint/recommended',
// consider disabling this class of rules if linting takes too long
'plugin:@typescript-eslint/recommended-requiring-type-checking',
// https://eslint.vuejs.org/rules/#priority-a-essential-error-prevention
// consider switching to `plugin:vue/strongly-recommended` or `plugin:vue/recommended` for stricter rules
'plugin:vue/essential',
// --- ONLY WHEN USING PRETTIER ---
// https://github.com/prettier/eslint-config-prettier#installation
// usage with Prettier, provided by 'eslint-config-prettier'.
'prettier',
'prettier/@typescript-eslint',
'prettier/vue',
],
plugins: [
// required to apply rules which need type information
'@typescript-eslint',
// https://eslint.vuejs.org/user-guide/#why-doesn-t-it-work-on-vue-file
// required to lint *.vue files
'vue',
],
// add your custom rules here
rules: {
// others rules...
// TypeScript
'quotes': ['warn', 'single'],
'@typescript-eslint/explicit-function-return-type': 'off',
}
}If anything goes wrong, read the typescript-eslint guide, on which this example is based.
As a last step, update your yarn lint command to also lint .ts files.
TIP
TypeScript Linting is really slow due to type-checking overhead, we suggest you to disable Webpack lint extension into the /quasar.config file for dev builds.
If you setup TypeScript linting and want fork-ts-checker-webpack-plugin (provided by @quasar/app-webpack package) to take it into account then you should make use of tsCheckerConfig property:
module.exports = function (ctx) {
return {
supportTS: {
tsCheckerConfig: {
eslint: {
enabled: true,
files: './src/**/*.{ts,tsx,js,jsx,vue}'
}
}
},
....
}
}