A basic svelte checker

package.json

@@ -55,6 +55,7 @@
     "rimraf": "^3.0.2",
     "semver": "^7.3.5",
     "strip-ansi": "^7.0.0",
+    "svelte-language-server": "^0.14.7",
     "ts-jest": "^27.0.3",
     "typescript": "^4.2.2",
     "vite": "^2.3.8",

packages/vite-plugin-checker/src/checkers/svelte/main.ts

@@ -0,0 +1,152 @@
+import os from 'os'
+import path from 'path'
+import * as fs from 'fs'
+import invariant from 'tiny-invariant'
+import { URI } from 'vscode-uri'
+import { watch } from 'chokidar'
+import { SvelteCheck } from 'svelte-language-server'
+import { parentPort } from 'worker_threads'
+
+import { Checker } from '../../Checker'
+import {
+  diagnosticToTerminalLog,
+  diagnosticToViteError,
+  normalizeLspDiagnostic,
+} from '../../logger'
+
+import type { CreateDiagnostic } from '../../types'
+
+// based off the class in svelte-check/src/index.ts
+class DiagnosticsWatcher {
+  private updateDiagnostics: any
+  private svelteCheck: SvelteCheck
+  private overlay: boolean
+
+  public constructor(root: string, overlay: boolean) {
+    this.overlay = overlay
+    this.svelteCheck = new SvelteCheck(root, {
+      compilerWarnings: {},
+      diagnosticSources: ['js', 'svelte', 'css'],
+    })
+
+    watch(`${root}/**/*.{svelte,d.ts,ts,js}`, {
+      ignored: ['node_modules'].map((ignore) => path.join(root, ignore)),
+      ignoreInitial: false,
+    })
+      .on('add', (path) => this.updateDocument(path, true))
+      .on('unlink', (path) => this.removeDocument(path))
+      .on('change', (path) => this.updateDocument(path, false))
+  }
+
+  private async updateDocument(path: string, isNew: boolean) {
+    const text = fs.readFileSync(path, 'utf-8')
+    await this.svelteCheck.upsertDocument({ text, uri: URI.file(path).toString() }, isNew)
+    this.scheduleDiagnostics()
+  }
+
+  private async removeDocument(path: string) {
+    await this.svelteCheck.removeDocument(URI.file(path).toString())
+    this.scheduleDiagnostics()
+  }
+
+  private scheduleDiagnostics() {
+    clearTimeout(this.updateDiagnostics)
+    this.updateDiagnostics = setTimeout(async () => {
+      let logChunk = ''
+      try {
+        const ds = await this.svelteCheck.getDiagnostics()
+        let currErr = null
+
+        for (const { filePath, text, diagnostics } of ds) {
+          for (const diagnostic of diagnostics) {
+            const formattedDiagnostic = normalizeLspDiagnostic({
+              diagnostic,
+              absFilePath: filePath,
+              fileText: text,
+              checker: 'svelte',
+            })
+
+            if (currErr === null) {
+              currErr = diagnosticToViteError(formattedDiagnostic)
+            }
+            logChunk += os.EOL + diagnosticToTerminalLog(formattedDiagnostic, 'svelte')
+          }
+        }
+
+        if (this.overlay) {
+          parentPort?.postMessage({
+            type: 'ERROR',
+            payload: {
+              type: 'error',
+              err: currErr,
+            },
+          })
+        }
+
+        console.log(logChunk)
+      } catch (err) {
+        if (this.overlay) {
+          parentPort?.postMessage({
+            type: 'ERROR',
+            payload: {
+              type: 'error',
+              err: err.message,
+            },
+          })
+        }
+        console.error(err.message)
+      }
+    }, 1000)
+  }
+}
+
+const createDiagnostic: CreateDiagnostic<'svelte'> = (pluginConfig) => {
+  let overlay = true // Vite defaults to true
+
+  return {
+    config: ({ hmr }) => {
+      const viteOverlay = !(typeof hmr === 'object' && hmr.overlay === false)
+
+      if (pluginConfig.overlay === false || !viteOverlay) {
+        overlay = false
+      }
+    },
+    configureServer({ root }) {
+      invariant(pluginConfig.svelte, 'config.svelte should be `false`')
+      let svelteRoot = root
+
+      if (pluginConfig.svelte !== true && pluginConfig.svelte.root) {
+        svelteRoot = pluginConfig.svelte.root
+      }
+
+      let watcher = new DiagnosticsWatcher(svelteRoot, overlay)
+      return watcher
+    },
+  }
+}
+
+export class SvelteChecker extends Checker<'svelte'> {
+  public constructor() {
+    super({
+      name: 'svelte',
+      absFilePath: __filename,
+      build: {
+        buildBin: (_config) => {
+          return ['svelte-check', []]
+        },
+      },
+      createDiagnostic,
+    })
+  }
+
+  public init() {
+    const createServeAndBuild = super.initMainThread()
+    module.exports.createServeAndBuild = createServeAndBuild
+
+    super.initWorkerThread()
+  }
+}
+
+const svelteChecker = new SvelteChecker()
+svelteChecker.prepare()
+svelteChecker.init()

packages/vite-plugin-checker/src/logger.ts

@@ -53,7 +53,7 @@ export enum DiagnosticLevel {
 
 export function diagnosticToTerminalLog(
   d: NormalizedDiagnostic,
-  name?: 'TypeScript' | 'vue-tsc' | 'VLS' | 'ESLint'
+  name?: 'TypeScript' | 'vue-tsc' | 'VLS' | 'ESLint' | 'svelte'
 ): string {
   const nameInLabel = name ? `(${name})` : ''
   const boldBlack = chalk.bold.rgb(0, 0, 0)
@@ -180,10 +180,12 @@ export function normalizeLspDiagnostic({
   diagnostic,
   absFilePath,
   fileText,
+  checker = 'VLS',
 }: {
   diagnostic: LspDiagnostic
   absFilePath: string
   fileText: string
+  checker?: string
 }): NormalizedDiagnostic {
   let level = DiagnosticLevel.Error
   const loc = lspRange2Location(diagnostic.range)
@@ -210,7 +212,7 @@ export function normalizeLspDiagnostic({
     codeFrame,
     stripedCodeFrame: codeFrame && strip(codeFrame),
     id: absFilePath,
-    checker: 'VLS',
+    checker,
     loc,
     level,
   }

packages/vite-plugin-checker/src/main.ts

@@ -19,7 +19,13 @@ export * from './codeFrame'
 export * from './worker'
 
 const sharedConfigKeys: (keyof SharedConfig)[] = ['enableBuild', 'overlay']
-const buildInCheckerKeys: BuildInCheckerNames[] = ['typescript', 'vueTsc', 'vls', 'eslint']
+const buildInCheckerKeys: BuildInCheckerNames[] = [
+  'typescript',
+  'vueTsc',
+  'vls',
+  'eslint',
+  'svelte',
+]
 
 function createCheckers(userConfig: UserPluginConfig, env: ConfigEnv): ServeAndBuildChecker[] {
   const serveAndBuildCheckers: ServeAndBuildChecker[] = []

packages/vite-plugin-checker/src/types.ts

@@ -45,6 +45,13 @@ export type EslintConfig =
       // watchDelay?: number
     }
 
+export type SvelteConfig =
+  | boolean
+  | Partial<{
+      root?: string
+      // TODO: support svelte config
+    }>
+
 /** checkers shared configuration */
 export interface SharedConfig {
   /**
@@ -65,6 +72,7 @@ export interface BuildInCheckers {
   vueTsc: VueTscConfig
   vls: VlsConfig
   eslint: EslintConfig
+  svelte: SvelteConfig
 }
 
 export type BuildInCheckerNames = keyof BuildInCheckers