[#IP-86] tslint to eslint migration

.eslintignore

@@ -0,0 +1,9 @@
+# Never lint node_modules
+node_modules
+
+# We shouldn't lint assets nor generated files
+generated
+
+**/__tests__/*
+**/__mocks__/*
+Dangerfile.*

.eslintrc.js

@@ -0,0 +1,22 @@
+module.exports = {
+  env: {
+    browser: true,
+    es6: true,
+    node: true
+  },
+  ignorePatterns: [
+    "node_modules",
+    "generated",
+    "**/__tests__/*",
+    "**/__mocks__/*",
+    "Dangerfile.*",
+    "*.d.ts"
+  ],
+  parser: "@typescript-eslint/parser",
+  parserOptions: {
+    project: "tsconfig.json",
+    sourceType: "module"
+  },
+  extends: ["@pagopa/eslint-config/strong"],
+  rules: {}
+};

.gitignore

@@ -6,3 +6,7 @@ coverage
 .vscode
 obj
 bin
+
+# eslint section
+!.eslintrc.js
+.eslintcache

Dangerfile.ts

@@ -1,7 +1,7 @@
 // import custom DangerJS rules
 // see http://danger.systems/js
 // see https://github.com/teamdigitale/danger-plugin-digitalcitizenship/
-// tslint:disable-next-line:prettier
+// eslint-disable-next-line prettier/prettier
 import checkDangers from 'danger-plugin-digitalcitizenship';
 
 checkDangers();

package.json

@@ -18,11 +18,13 @@
     "start": "npm-run-all --parallel start:host watch",
     "pretest": "npm run build",
     "test": "jest -i",
-    "lint": "tslint --project .",
+    "lint": "eslint . -c .eslintrc.js --ext .ts,.tsx",
     "preversion": "auto-changelog  --config .auto-changelog.json --unreleased --commit-limit false --stdout --template preview.hbs",
     "version": "auto-changelog -p --config .auto-changelog.json --unreleased && git add CHANGELOG.md"
   },
   "devDependencies": {
+    "eslint-plugin-prettier": "^3.3.1",
+    "@pagopa/eslint-config": "^1.1.1",
     "@azure/functions": "^1.0.3",
     "@types/express": "^4.17.2",
     "@types/express-serve-static-core": "^4.17.2",
@@ -33,14 +35,12 @@
     "danger": "^9.2.0",
     "danger-plugin-digitalcitizenship": "*",
     "express": "^4.17.1",
-    "italia-tslint-rules": "*",
     "jest": "^24.8.0",
     "npm-run-all": "^4.1.5",
     "prettier": "^1.12.1",
     "rimraf": "^2.6.2",
     "tree-kill": "^1.2.2",
     "ts-jest": "^24.0.2",
-    "tslint": "^5.1.0",
     "typescript": "^3.5.0"
   },
   "peerDependencies": {

src/ExpressAdapter.ts

@@ -1,5 +1,5 @@
-import { Context } from "@azure/functions";
 import EventEmitter = require("events");
+import { Context } from "@azure/functions";
 import { Application } from "express";
 
 import IncomingMessage from "./IncomingMessage";
@@ -10,7 +10,7 @@ import OutgoingMessage from "./OutgoingMessage";
  * @throws {Error}
  * @private
  */
-// tslint:disable-next-line: no-any
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 const isValidContext = (context: any): context is Context =>
   context !== undefined &&
   typeof context === "object" &&
@@ -21,7 +21,7 @@ const isValidContext = (context: any): context is Context =>
   context.bindings.req.originalUrl &&
   typeof context.bindings.req.originalUrl === "string";
 
-export type RequestListener = (...args: readonly unknown[]) => void;
+export type RequestListener = (...args: ReadonlyArray<unknown>) => void;
 
 /**
  * Express adapter allowing to handle Azure Function requests by wrapping in request events.
@@ -33,7 +33,7 @@ export default class ExpressAdapter extends EventEmitter {
   /**
    * @param {Object=} application Request listener (typically an express/connect instance)
    */
-  public constructor(application: Application) {
+  constructor(application: Application) {
     super();
 
     if (application !== undefined) {
@@ -53,25 +53,27 @@ export default class ExpressAdapter extends EventEmitter {
   /**
    * Create function ready to be exposed to Azure Function for request handling.
    */
-  public createAzureFunctionHandler = () => (context: Context) => {
-    if (!isValidContext(context)) {
-      return;
-    }
+  public createAzureFunctionHandler() {
+    return (context: Context): void => {
+      if (!isValidContext(context)) {
+        return;
+      }
 
-    const updateResponse = (
-      updater: (
-        prev: NonNullable<Context["res"]>
-      ) => NonNullable<Context["res"]>
-    ) => {
-      // tslint:disable-next-line: no-object-mutation
-      context.res = updater(context.res || {});
-    };
+      const updateResponse = (
+        updater: (
+          prev: NonNullable<Context["res"]>
+        ) => NonNullable<Context["res"]>
+      ): void => {
+        // eslint-disable-next-line functional/immutable-data
+        context.res = updater(context.res || {});
+      };
 
-    // 2. Wrapping
-    const req = new IncomingMessage(context);
-    const res = new OutgoingMessage(updateResponse, context.done);
+      // 2. Wrapping
+      const req = new IncomingMessage(context);
+      const res = new OutgoingMessage(updateResponse, context.done);
 
-    // 3. Synchronously calls each of the listeners registered for the event
-    this.emit("request", req, res);
-  };
+      // 3. Synchronously calls each of the listeners registered for the event
+      this.emit("request", req, res);
+    };
+  }
 }

src/IncomingMessage.ts

@@ -1,34 +1,32 @@
-import { Context } from "@azure/functions";
 import { Socket } from "net";
 import { Readable } from "stream";
 import { TLSSocket } from "tls";
+import { Context } from "@azure/functions";
 
-const NOOP = () => true;
+const NOOP = (): true => true;
 
-function removePortFromAddress(address: string): string {
-  return address ? address.replace(/:[0-9]*$/, "") : address;
-}
+const removePortFromAddress = (address: string): string =>
+  address ? address.replace(/:[0-9]*$/, "") : address;
 
 /**
  * Create a fake connection object
  *
  * @param {Object} context Raw Azure context object for a single HTTP request
  * @returns {object} Connection object
  */
-function createConnectionObject(
+const createConnectionObject = (
   context: Context
-): Pick<Socket, "remoteAddress"> & Pick<TLSSocket, "encrypted"> {
+): Pick<Socket, "remoteAddress"> & Pick<TLSSocket, "encrypted"> => {
   const { req } = context.bindings;
   const xForwardedFor = req.headers
     ? req.headers["x-forwarded-for"]
     : undefined;
 
   return {
-    encrypted:
-      req.originalUrl && req.originalUrl.toLowerCase().startsWith("https"),
+    encrypted: req.originalUrl?.toLowerCase().startsWith("https"),
     remoteAddress: removePortFromAddress(xForwardedFor)
   };
-}
+};
 
 /**
  * Copy useful context properties from the native context provided by the Azure
@@ -41,15 +39,13 @@ function createConnectionObject(
  * @param {Object} context Raw Azure context object for a single HTTP request
  * @returns {Object} Filtered context
  */
-function sanitizeContext(context: Context): Context {
-  return {
-    ...context,
-    // We don't want the developer to mess up express flow
-    // See https://github.com/yvele/azure-function-express/pull/12#issuecomment-336733540
-    done: NOOP,
-    log: context.log.bind(context)
-  };
-}
+const sanitizeContext = (context: Context): Context => ({
+  ...context,
+  // We don't want the developer to mess up express flow
+  // See https://github.com/yvele/azure-function-express/pull/12#issuecomment-336733540
+  done: NOOP,
+  log: context.log.bind(context)
+});
 
 /**
  * Request object wrapper
@@ -79,7 +75,7 @@ export default class IncomingMessage extends Readable {
       context: sanitizeContext(context), // Specific to Azure Function
       headers: req.headers || {}, // Should always have a headers object
       socket: { destroy: NOOP },
-      // tslint:disable-next-line: no-any
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
       url: (req as any).originalUrl
     });
   }

src/OutgoingMessage.ts

@@ -1,11 +1,11 @@
-// tslint:disable: variable-name
+// eslint-disable camelcase
 
-import { Context } from "@azure/functions";
 import {
   OutgoingHttpHeaders,
   OutgoingMessage as NativeOutgoingMessage,
   ServerResponse
 } from "http";
+import { Context } from "@azure/functions";
 
 import { statusCodes } from "./statusCodes";
 
@@ -17,12 +17,13 @@ import { statusCodes } from "./statusCodes";
  * @private
  */
 export default class OutgoingMessage extends NativeOutgoingMessage {
-  public _hasBody = true;
-  public _headerNames = {};
-  public _headers = null;
-  public _removedHeader = {};
+  public readonly _hasBody = true;
+  public readonly _headerNames = {};
+  public readonly _headers = null;
+  public readonly _removedHeader = {};
+  // eslint-disable-next-line functional/prefer-readonly-type
   public statusMessage!: string;
-  public statusCode!: number;
+  public readonly statusCode!: number;
 
   /**
    * Original implementation: https://github.com/nodejs/node/blob/v6.x/lib/_http_outgoing.js#L48
@@ -40,27 +41,29 @@ export default class OutgoingMessage extends NativeOutgoingMessage {
 
   // Those methods cannot be prototyped because express explicitelly overrides __proto__
   // See https://github.com/expressjs/express/blob/master/lib/middleware/init.js#L29
-  public end: NativeOutgoingMessage["end"] = (
-    // tslint:disable-next-line: no-any
-    chunkOrCb?: any
+  public readonly end: NativeOutgoingMessage["end"] = (
+    chunkOrCb: Parameters<NativeOutgoingMessage["end"]>[0]
   ) => {
     // 1. Write head
+    // eslint-disable-next-line no-invalid-this
     this.writeHead(this.statusCode); // Make jshttp/on-headers able to trigger
 
     // 2. Return raw body to Azure Function runtime
+    // eslint-disable-next-line no-invalid-this
     this.updateResponse(res => ({
       ...res,
       body: chunkOrCb,
       isRaw: true
     }));
+    // eslint-disable-next-line no-invalid-this
     this.done();
   };
 
   /**
    * https://nodejs.org/api/http.html#http_response_writehead_statuscode_statusmessage_headers
    * Original implementation: https://github.com/nodejs/node/blob/v6.x/lib/_http_server.js#L160
    */
-  public writeHead: ServerResponse["writeHead"] = (
+  public readonly writeHead: ServerResponse["writeHead"] = (
     statusCode: number,
     reasonOrHeaders?: string | OutgoingHttpHeaders,
     headersOrUndefined?: OutgoingHttpHeaders
@@ -72,7 +75,7 @@ export default class OutgoingMessage extends NativeOutgoingMessage {
     }
 
     // 2. Status message
-    // tslint:disable-next-line: no-object-mutation
+    // eslint-disable-next-line functional/immutable-data, no-invalid-this
     this.statusMessage =
       typeof reasonOrHeaders === "string"
         ? reasonOrHeaders
@@ -85,24 +88,28 @@ export default class OutgoingMessage extends NativeOutgoingMessage {
         ? reasonOrHeaders
         : headersOrUndefined;
 
+    // eslint-disable-next-line no-underscore-dangle, no-invalid-this
     if (this._headers && headers !== undefined) {
       // Slow-case: when progressive API and header fields are passed.
       Object.keys(headers).forEach(k => {
         const v = headers[k];
         if (v) {
+          // eslint-disable-next-line no-invalid-this
           this.setHeader(k, v);
         }
       });
     }
 
     // 4. Sets everything
+    // eslint-disable-next-line no-invalid-this
     this.updateResponse(res => ({
       ...res,
       // In order to uniformize node 6 behaviour with node 8 and 10,
       // we want to never have undefined headers, but instead empty object
       headers:
+        // eslint-disable-next-line no-underscore-dangle, no-invalid-this
         this._headers && headers === undefined
-          ? // tslint:disable-next-line: no-any
+          ? // eslint-disable-next-line no-underscore-dangle, @typescript-eslint/no-explicit-any, no-invalid-this
             (this as any)._renderHeaders()
           : headers !== undefined
           ? headers

src/__tests__/index.test.ts

@@ -5,29 +5,29 @@ import * as qs from "querystring";
 // do not convert to default import despite vscode hints :-)
 import * as treeKill from "tree-kill";
 
-// tslint:disable-next-line: no-let
+// eslint-disable-next-line functional/no-let
 let spawnedFunc: ChildProcess;
-// tslint:disable-next-line: no-let
+// eslint-disable-next-line functional/no-let
 let funcAddress: string;
-// tslint:disable-next-line: no-let
+// eslint-disable-next-line functional/no-let
 let isStopping = false;
 
 // do not reject promise on non-200 statuses
-// tslint:disable-next-line: no-object-mutation
+// eslint-disable-next-line functional/immutable-data
 axios.defaults.validateStatus = () => true;
 
 const startFunc = () =>
-  // tslint:disable-next-line: promise-must-complete
+  // eslint-disable-next-line @typescript-eslint/no-floating-promises
   new Promise<{ p: ChildProcess; address: string }>(res => {
     const func = spawn("func", ["start"]);
     func.stdout.on("data", data => {
       if (!isStopping) {
-        // tslint:disable-next-line: no-console
+        // eslint-disable-next-line no-console
         console.log(`${data}`);
       }
       const matches = String(data).match(/(http:\/\/[^{]+)/);
       if (matches && matches[1]) {
-        // tslint:disable-next-line: no-console
+        // eslint-disable-next-line no-console
         console.log("serving function at %s", matches[1]);
         res({
           address: matches[1],

src/createAzureFunctionsHandler.ts

@@ -9,9 +9,11 @@ import ExpressAdapter from "./ExpressAdapter";
  * @param {Object} requestListener Request listener (typically an express/connect instance)
  * @returns {function(context: Object)} Azure Function handle
  */
-export default function createAzureFunctionHandler(
+const createAzureFunctionHandler = (
   application: Application
-): (context: Context) => void {
+): ((context: Context) => void) => {
   const adapter = new ExpressAdapter(application);
   return adapter.createAzureFunctionHandler();
-}
+};
+
+export default createAzureFunctionHandler;

src/statusCodes.ts

@@ -1,4 +1,4 @@
-export const statusCodes: { [key: number]: string | undefined } = {
+export const statusCodes: { readonly [key: number]: string | undefined } = {
   100: "Continue",
   101: "Switching Protocols",
   102: "Processing", // RFC 2518, obsoleted by RFC 4918