replace tslint by typescript-eslint (#1979)

* replace tslint by typescript-eslint

* remove tslint config file and comments

* Fix  eslint issue in src directory

* Migrate simple eslint rules in __test__ directory

* use stricter types in __tests__ directory

* Fix or ignore all eslint issues in website directory

* Ignore eslint report in main immutable.d.ts file for now

.eslintignore

@@ -2,3 +2,4 @@
 /pages/generated/**
 /dist/**
 node_modules
+/type-definitions/flow-tests

.eslintrc.json

@@ -1,11 +1,17 @@
 {
   "root": true,
+  "parser": "@typescript-eslint/parser",
   "parserOptions": {
     "ecmaVersion": 6,
     "sourceType": "module"
   },
-  "extends": ["airbnb", "prettier"],
-  "plugins": ["react", "prettier"],
+  "extends": [
+    "airbnb",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:import/typescript",
+    "prettier"
+  ],
+  "plugins": ["react", "prettier", "@typescript-eslint"],
   "rules": {
     "array-callback-return": "off",
     "block-scoped-var": "off",
@@ -35,7 +41,7 @@
     "no-this-before-super": "off",
     "no-underscore-dangle": "off",
     "no-unused-expressions": "off",
-    "no-unused-vars": "error",
+    "no-unused-vars": "off",
     "no-use-before-define": "off",
     "no-useless-concat": "error",
     "no-var": "error",
@@ -61,10 +67,15 @@
     "react/self-closing-comp": "error",
     "react/sort-comp": "off",
     "react/jsx-props-no-spreading": "off",
+    "react/require-default-props": [
+      "error",
+      {
+        "functions": "ignore"
+      }
+    ],
     "jsx-a11y/no-static-element-interactions": "off",
     "import/extensions": [
       "error",
-      "always",
       { "js": "never", "ts": "never", "tsx": "never" }
     ],
     "import/newline-after-import": "error",
@@ -74,6 +85,39 @@
     "import/no-unresolved": "error",
     "import/no-useless-path-segments": "off",
     "import/prefer-default-export": "off",
-    "prettier/prettier": "error"
-  }
+    "prettier/prettier": "error",
+    "@typescript-eslint/no-unused-vars": [
+      "error",
+      { "argsIgnorePattern": "^_" }
+    ]
+  },
+  "overrides": [
+    {
+      "files": ["__tests__/*"],
+      "rules": {
+        "import/no-unresolved": [
+          "error",
+          {
+            "ignore": ["immutable"]
+          }
+        ]
+      }
+    },
+
+    {
+      "files": ["type-definitions/ts-tests/*"],
+      "rules": {
+        "no-lone-blocks": "off",
+        "@typescript-eslint/no-explicit-any": "off",
+        "@typescript-eslint/no-unused-vars": "off",
+        "prefer-const": "off",
+        "import/no-unresolved": [
+          "error",
+          {
+            "ignore": ["immutable"]
+          }
+        ]
+      }
+    }
+  ]
 }

__tests__/Comparator.ts

@@ -6,11 +6,12 @@ const expectedSortedNumbers: readonly number[] = [
   7, 95, 90, 92, 3, 5, 9, 4, 6, 10, 12,
 ];
 
+/* eslint-disable no-else-return */
 const testComparator: Comparator<number> = (left, right) => {
   //The number 7 always goes first...
-  if (left == 7) {
+  if (left === 7) {
     return PairSorting.LeftThenRight;
-  } else if (right == 7) {
+  } else if (right === 7) {
     return PairSorting.RightThenLeft;
   }
 
@@ -31,6 +32,7 @@ const testComparator: Comparator<number> = (left, right) => {
   //...and, finally, sort the numbers of each subgroup in ascending order.
   return left - right;
 };
+/* eslint-enable no-else-return */
 
 describe.each([
   ['List', List],

__tests__/Conversion.ts

@@ -1,10 +1,7 @@
 import { fromJS, is, List, Map, OrderedMap, Record } from 'immutable';
-
 import * as jasmineCheck from 'jasmine-check';
-jasmineCheck.install();
 
-// Symbols
-declare function Symbol(name: string): any;
+jasmineCheck.install();
 
 describe('Conversion', () => {
   // Note: order of keys based on Map's hashing order
@@ -107,7 +104,9 @@ describe('Conversion', () => {
   });
 
   it('Throws when provided circular reference', () => {
-    const o = { a: { b: { c: null as any } } };
+    type OType = { a: { b: { c: OType | null } } };
+
+    const o: OType = { a: { b: { c: null } } };
     o.a.b.c = o;
     expect(() => fromJS(o)).toThrow(
       'Cannot convert circular structure to Immutable'
@@ -117,7 +116,8 @@ describe('Conversion', () => {
   it('Converts deep JSON with custom conversion', () => {
     const seq = fromJS(js, function (key, sequence) {
       if (key === 'point') {
-        return new Point(sequence as any);
+        // @ts-expect-error -- to convert to real typing
+        return new Point(sequence);
       }
       return Array.isArray(this[key])
         ? sequence.toList()
@@ -128,7 +128,8 @@ describe('Conversion', () => {
   });
 
   it('Converts deep JSON with custom conversion including keypath if requested', () => {
-    const paths: Array<any> = [];
+    const paths: Array<Array<string | number> | undefined> = [];
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
     const seq1 = fromJS(js, function (key, sequence, keypath) {
       expect(arguments.length).toBe(3);
       paths.push(keypath);
@@ -147,6 +148,8 @@ describe('Conversion', () => {
       ['point'],
       ['list'],
     ]);
+
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
     const seq2 = fromJS(js, function (key, sequence) {
       expect(arguments[2]).toBe(undefined);
     });

__tests__/Equality.ts

@@ -1,6 +1,6 @@
 import { is, List, Map, Seq, Set } from 'immutable';
-
 import * as jasmineCheck from 'jasmine-check';
+
 jasmineCheck.install();
 
 describe('Equality', () => {
@@ -53,8 +53,8 @@ describe('Equality', () => {
   });
 
   it('dereferences things', () => {
-    const ptrA = { foo: 1 },
-      ptrB = { foo: 2 };
+    const ptrA = { foo: 1 };
+    const ptrB = { foo: 2 };
     expectIsNot(ptrA, ptrB);
     ptrA.valueOf = ptrB.valueOf = function () {
       return 5;
@@ -66,11 +66,13 @@ describe('Equality', () => {
     };
     expectIs(ptrA, ptrB);
     ptrA.valueOf = ptrB.valueOf = function () {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
       return null as any;
     };
     expectIs(ptrA, ptrB);
     ptrA.valueOf = ptrB.valueOf = function () {
-      return void 0 as any;
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      return undefined as any;
     };
     expectIs(ptrA, ptrB);
     ptrA.valueOf = function () {

__tests__/IndexedSeq.ts

@@ -1,6 +1,6 @@
 import { Seq } from 'immutable';
-
 import * as jasmineCheck from 'jasmine-check';
+
 jasmineCheck.install();
 
 describe('IndexedSequence', () => {

__tests__/KeyedSeq.ts

@@ -1,6 +1,6 @@
 import { Range, Seq } from 'immutable';
-
 import * as jasmineCheck from 'jasmine-check';
+
 jasmineCheck.install();
 
 describe('KeyedSeq', () => {
@@ -11,7 +11,8 @@ describe('KeyedSeq', () => {
     const seqEntries = seq.entries();
     const keyedEntries = keyed.entries();
 
-    let seqStep, keyedStep;
+    let seqStep;
+    let keyedStep;
     do {
       seqStep = seqEntries.next();
       keyedStep = keyedEntries.next();