npm run watch/hot only successful on the first run

Question

Background:

I added TypeScript support to my existing project, so I added ts-loader and typescript. I think, I configured everything right and it is working fine in dev and prod mode.

I would like to update gradually, keeping all the JavaScript code in place and using TypeScript for everything new or where there is a need for refactoring. So it may be important to note that TableValue.vue is an old js component.

Problem:

Edit: It also occurs with npm run watch

When I run npm run hot in package.json: "scripts": { ..., "hot": "mix watch --hot", ...} it only works on the first try. As soon as I change any file and trigger a recompile, I get:

√ Mix: Compiled successfully in 19.15s
webpack compiled successfully

// Here the recompile is triggered
i Compiling Mix
√ Mix: Compiled with some errors in 509.01ms
ERROR in C:\fakepath\resources\js\components\test\component.vue.ts
24:23-41
[tsl] ERROR in C:\fakepath\resources\js\components\test\component.vue.ts(24,24)
      TS2307: Cannot find module './TableValue.vue' or its corresponding type declarations.

webpack compiled with 1 error

I suspect that this error comes from ts-loader, but why is everything working on the first try?

I could just ignore this error, but then hot module replacement is unusable, because I have to manually trigger a new build process every time anyway.

• Has someone got such an setup working?
• What can I do to solve this error?

---

Infos:

I'm working with:

• Laravel 8.58
• Laravel Mix 6.0.25
• Vue 2.6.14
• ts-loader 9.2.5
• typescript 4.4.2

Here the script tag from the test component:

<script lang="ts">
import Vue, { PropType } from 'vue';

import TableValue from "./TableValue.vue";
import Model from "@/js/types/model.js";

export default Vue.extend({
  name: "TestComponent",
  components: {
    TableValue
  },
  props: {
    'model': {
      type: Object as PropType<Model>,
      required: true
    }
  },
  data() {
    return {};
  },
});
</script>

Project Structure:

app/
bootstrap/
config/
database/
node_modules/
public/
resources/
  js/
    components/
    store/
    types/
    views/
    app.js
    bootstrap.js
    routes.js
    shims-vue.d.ts
  lang/
  sass/
  views/
routes/
storage/
tests/
vendor/
composer.json
composer.lock
tsconfig.json
package-lock.json
package.json
phpunit.xml
vs.code-workspace
webpack.mix.js

webpack.mix.js:

const mix = require('laravel-mix');
const ResolveTypeScriptPlugin = require("resolve-typescript-plugin").default;

mix.webpackConfig({
    module: {
        rules: [
            {
                test: /\.tsx?$/,
                loader: "ts-loader",
                options: { appendTsSuffixTo: [/\.vue$/] },
                exclude: /node_modules/
            }
        ]
    },
    resolve: {
        extensions: ['.js', '.ts', '.vue'],
        alias: {
            '@': __dirname + '/resources'
        },
        fullySpecified: false,
        plugins: [new ResolveTypeScriptPlugin()]
    },
    devtool: 'source-map'
}).sourceMaps();

mix.ts('resources/js/app.js', 'public/js')
    .sass('resources/sass/app.sass', 'public/css').sourceMaps()
    .vue();

mix.extract();

tsconfig.json:

{
    "compilerOptions": {
        "target": "esnext",
        "module": "esnext",
        "strict": true,
        "noImplicitAny": false,
        "importHelpers": true,
        "moduleResolution": "node",
        "esModuleInterop": true,
        "allowSyntheticDefaultImports": true,
        "allowJs": true,
        "checkJs": false,
        "sourceMap": true,
        "baseUrl": ".",
        "paths": {
            "@/*": [
                "resources/*"
            ]
        },
        "lib": [
            "esnext",
            "dom",
            "dom.iterable",
            "scripthost"
        ]
    },
    "files": [
        "resources/js/shims-vue.d.ts"
    ],
    "include": [
        "resources/js/**/*.ts",
        "resources/js/**/*.vue",
    ],
    "exclude": [
        "node_modules",
        ".vscode",
        "app",
        "bootstrap",
        "config",
        "database",
        "public",
        "routes",
        "storage",
        "tests",
        "vendor"
    ]
}

Update:

When I remove shims-vue.d.ts, I get the error immediately.

declare module "*.vue" {
    import Vue from "vue";
    export default Vue;
}

It looks like this file is only read/applyed once and not after? Not sure.

Tacnode

Is this just with hot or is it also with watch? – Guanidine

The problem is also there with watch. It works on the first try, but as soon as I change any file, I get the same error. – Tacnode

Answer 1

It looks like ts-loader doesn't support HMR yet.

• https://github.com/TypeStrong/ts-loader#hot-module-replacement

I installed fork-ts-checker-webpack-plugin and updated webpack.mix.js to:

const mix = require('laravel-mix');
const path = require('path');

const ResolveTypeScriptPlugin = require("resolve-typescript-plugin").default;
const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin');

mix.webpackConfig({
    module: {
        rules: [
            {
                test: /\.tsx?$/,
                loader: "ts-loader",
                options: {
                    appendTsSuffixTo: [/\.vue$/],
                    transpileOnly: true
                },
                exclude: /node_modules/
            }
        ]
    },
    resolve: {
        extensions: ['.js', '.ts', '.tsx', '.vue'],
        alias: {
            '@': path.resolve(__dirname + '/resources'),
            '@store': path.resolve(__dirname + '/resources/js/store'),
            '@components': path.resolve(__dirname + '/resources/js/components')
        },
        fullySpecified: false,
        plugins: [new ResolveTypeScriptPlugin()]
    },
    plugins: [new ForkTsCheckerWebpackPlugin()],
    devtool: 'source-map'
}).sourceMaps();

mix.ts('resources/js/app.js', 'public/js')
    .sass('resources/sass/app.sass', 'public/css').sourceMaps()
    .vue();

mix.extract();

Now everything is working fine but I'm still not sure why watch was also affected and where exactly the problem was.

Tacnode

For me issue hasn't resolved even after configuring ForkTsCheckerWebpackPlugin my problem is that in my .d.ts file I'm declaring global variable like this declare const DOTNET_API_ENDPOINT: string; typescript doesn't give any error on first run, however if I trigger hot refresh by changing something in my component, it would the show TS2304: Cannot find name 'DOTNET_API_ENDPOINT'. on update. – Longcloth

Answer 2

I'm not using Typescript, but the same thing was happening to me, when i ran npm run watch/hot where only successful on the first change of the code, then, you can not see the changes until you run npm run watch/hot or npm run dev again. The strange thing was that everything was compiling successfully on every change I made.

I manage to debug it with git, and found out that I was importing a component with a wrong name but did not get an error on the console. My component name was WhosApplying.vue

I got:

import WhosApplying from "@/whosApplying.vue"

And change it for:

import WhosApplying from "@/WhosApplying.vue";

That mistake in the w instead of W make me lose hours. 😅

Saturated

Answer 3

I ran into this using laravel-mix after adding typescript to an Inertia / Vue 3 project.

Using Volar (Not Vuter)

To fix it I changed my webpack.config.js file from:

const path = require('path');

module.exports = {
    resolve: {
        alias: {
            '@': path.resolve('resources/js'),
        },
    },
};

to:

const path = require('path');

module.exports = {
    module: {
        rules: [
            {
                test: /\.tsx?$/,
                loader: "ts-loader",
                options: {
                    appendTsSuffixTo: [/\.vue$/],
                    transpileOnly: true
                },
                exclude: /node_modules/
            }
        ]
    },
    resolve: {
        extensions: ['.js', '.ts', '.tsx', '.vue'],
        alias: {
            '@': path.resolve(__dirname + '/resources/js'),
        },
    },
};

Igal