Lint Typescript

Author: wojpawlik

.eslintrc

@@ -1,4 +1,19 @@
 {
-  "extends": ["standard"],
+  "extends": ["standard-with-typescript"],
+  "parserOptions": {
+    "project": "./tsconfig.json"
+  },
+  "overrides": [
+    {
+      "files": "*.ts",
+      "extends": ["plugin:prettier/recommended", "prettier/@typescript-eslint"],
+      "rules": {
+        "@typescript-eslint/explicit-function-return-type": "off",
+        "@typescript-eslint/no-non-null-assertion": "warn",
+        "@typescript-eslint/promise-function-async": "off",
+        "@typescript-eslint/strict-boolean-expressions": "warn"
+      }
+    }
+  ],
   "plugins": ["ava"]
 }

.prettierrc.json

@@ -1,6 +1,4 @@
 {
-  "insertPragma": true,
-  "requirePragma": true,
   "semi": false,
   "singleQuote": true
 }

package.json

@@ -54,12 +54,17 @@
   },
   "devDependencies": {
     "@types/node": "^13.1.0",
+    "@typescript-eslint/eslint-plugin": "^3.5.0",
+    "@typescript-eslint/parser": "^3.5.0",
     "ava": "^3.0.0",
-    "eslint": "^6.2.2",
+    "eslint": "^7.4.0",
+    "eslint-config-prettier": "^6.11.0",
     "eslint-config-standard": "^14.1.0",
+    "eslint-config-standard-with-typescript": "^18.0.2",
     "eslint-plugin-ava": "^10.0.0",
     "eslint-plugin-import": "^2.2.0",
     "eslint-plugin-node": "^11.0.0",
+    "eslint-plugin-prettier": "^3.1.4",
     "eslint-plugin-promise": "^4.0.0",
     "eslint-plugin-standard": "^4.0.0",
     "husky": "^4.2.0",

src/composer.ts

@@ -190,12 +190,14 @@ class Composer<TContext extends Context> implements Middleware.Obj<TContext> {
 
   /**
    * Generates middleware that runs in the background.
+   * @deprecated
    */
   static fork<TContext extends Context>(
     middleware: Middleware<TContext>
   ): Middleware.Fn<TContext> {
     const handler = Composer.unwrap(middleware)
     return (ctx, next) => {
+      // eslint-disable-next-line @typescript-eslint/no-misused-promises
       setImmediate(handler, ctx, Composer.safePassThru())
       return next()
     }
@@ -316,6 +318,7 @@ class Composer<TContext extends Context> implements Middleware.Obj<TContext> {
       return entities?.some((entity) =>
         predicate(
           entity,
+          // eslint-disable-next-line @typescript-eslint/restrict-plus-operands
           text.substring(entity.offset, entity.offset + entity.length),
           ctx
         )
@@ -333,19 +336,19 @@ class Composer<TContext extends Context> implements Middleware.Obj<TContext> {
     if (fns.length === 0) {
       // prettier-ignore
       return Array.isArray(predicate)
-        //@ts-expect-error
+        // @ts-expect-error
         ? Composer.entity(entityType, ...predicate)
-        //@ts-expect-error
+        // @ts-expect-error
         : Composer.entity(entityType, predicate)
     }
     const triggers = normalizeTriggers(predicate)
-    //@ts-expect-error
+    // @ts-expect-error
     return Composer.entity(({ type }, value, ctx) => {
       if (type !== entityType) {
         return false
       }
       for (const trigger of triggers) {
-        //@ts-expect-error
+        // @ts-expect-error
         ctx.match = trigger(value, ctx)
         if (ctx.match) {
           return true
@@ -435,8 +438,8 @@ class Composer<TContext extends Context> implements Middleware.Obj<TContext> {
         (ctx.message && (ctx.message.caption || ctx.message.text)) ||
         (ctx.channelPost &&
           (ctx.channelPost.caption || ctx.channelPost.text)) ||
-        (ctx.callbackQuery && ctx.callbackQuery.data) ||
-        (ctx.inlineQuery && ctx.inlineQuery.query)
+        ctx.callbackQuery?.data ||
+        ctx.inlineQuery?.query
       for (const trigger of triggers) {
         const match = trigger(text, ctx)
         if (match) {
@@ -468,7 +471,7 @@ class Composer<TContext extends Context> implements Middleware.Obj<TContext> {
     ...fns: NonemptyReadonlyArray<Middleware<TContext>>
   ) {
     if (fns.length === 0) {
-      //@ts-expect-error
+      // @ts-expect-error
       return Composer.entity(['bot_command'], command)
     }
     const commands = normalizeTextArguments(command, '/')
@@ -478,7 +481,8 @@ class Composer<TContext extends Context> implements Middleware.Obj<TContext> {
         const groupCommands =
           ctx.me &&
           (ctx.chat.type === 'group' || ctx.chat.type === 'supergroup')
-            ? commands.map((command) => `${command}@${ctx.me}`)
+            ? // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
+              commands.map((command) => `${command}@${ctx.me}`)
             : []
         return Composer.entity(
           ({ offset, type }, value) =>

src/router.ts

@@ -48,7 +48,7 @@ class Router<TContext extends Context> implements Middleware.Obj<TContext> {
         }
         Object.assign(ctx, result.context)
         Object.assign(ctx.state, result.state)
-        return this.handlers.get(result.route) || this.otherwiseHandler
+        return this.handlers.get(result.route) ?? this.otherwiseHandler
       })
     })
   }

src/types.ts

@@ -1,20 +1,22 @@
 /** @format */
 
-//@ts-ignore
-import Context from './context'
+import type Context from './context'
 
+// eslint-disable-next-line @typescript-eslint/no-namespace
 export namespace Middleware {
-  export interface Fn<TContext extends Context> {
-    /*
-      next's parameter is in a contravariant position, and thus, trying to type it
-      prevents assigning `MiddlewareFn<ContextMessageUpdate>`
-      to `MiddlewareFn<CustomContext>`.
-      Middleware passing the parameter should be a separate type instead.
-    */
-    (ctx: TContext, next: () => Promise<void>): void | Promise<unknown>
-  }
+  /*
+    next's parameter is in a contravariant position, and thus, trying to type it
+    prevents assigning `MiddlewareFn<ContextMessageUpdate>`
+    to `MiddlewareFn<CustomContext>`.
+    Middleware passing the parameter should be a separate type instead.
+  */
+  export type Fn<TContext extends Context> = (
+    ctx: TContext,
+    next: () => Promise<void>
+    // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
+  ) => void | Promise<unknown>
   export interface Obj<TContext extends Context> {
-    middleware(): Fn<TContext>
+    middleware: () => Fn<TContext>
   }
 }
 export type Middleware<TContext extends Context> =

typings/telegram-types.d.ts

@@ -174,11 +174,7 @@ export type InputFile =
   | InputFileByBuffer
   | InputFileByURL
 
-
-export type DiceEmoji = 
-  '🎲' |
-  '🎯' |
-  '🏀'
+export type DiceEmoji = '🎲' | '🎯' | '🏀'
 
 /**
  * Sending video notes by a URL is currently unsupported
@@ -786,8 +782,8 @@ export interface Dice {
   /**
    * Emoji of the dice
    */
-  emoji: DiceEmoji,
-  
+  emoji: DiceEmoji
+
   /**
    * Value of the dice
    */