feat: Add rxjs-no-index rule.

See ReactiveX/rxjs#4230

package.json

@@ -78,7 +78,7 @@
     "test": "yarn run lint && yarn run test:build && yarn run test:mocha && yarn run test:tslint-v5 && yarn run test:tslint-v6 && yarn run test:tslint-v6-compat",
     "test:build": "yarn run test:clean && tsc -p tsconfig.json",
     "test:clean": "rimraf build",
-    "test:debug": "tslint --test \"./test/v6/fixtures/no-internal/**/tslint.json\"",
+    "test:debug": "tslint --test \"./test/v6/fixtures/no-index/**/tslint.json\"",
     "test:issues": "yarn run test:clean && tsc -p tsconfig.json && tslint --test \"./test/v6/fixtures/issues/**/tslint.json\"",
     "test:mocha": "mocha \"./build/**/*-spec.js\"",
     "test:tslint-v5": "yarn --cwd ./test/v5 install && yarn --cwd ./test/v5 upgrade && tslint --test \"./test/v5/fixtures/**/tslint.json\"",

source/rules/rxjsNoIndexRule.ts

@@ -0,0 +1,42 @@
+/**
+ * @license Use of this source code is governed by an MIT-style license that
+ * can be found in the LICENSE file at https://github.com/cartant/rxjs-tslint-rules
+ */
+/*tslint:disable:no-use-before-declare*/
+
+import * as Lint from "tslint";
+import * as ts from "typescript";
+
+export class Rule extends Lint.Rules.AbstractRule {
+  public static metadata: Lint.IRuleMetadata = {
+    deprecationMessage: undefined,
+    description: "Disallows the importation from index modules.",
+    options: null,
+    optionsDescription: "Not configurable.",
+    requiresTypeInfo: false,
+    ruleName: "rxjs-no-index",
+    type: "functionality",
+    typescriptOnly: false
+  };
+
+  public static FAILURE_STRING =
+    "RxJS imports from index modules are forbidden";
+
+  public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+    return this.applyWithWalker(new Walker(sourceFile, this.getOptions()));
+  }
+}
+
+class Walker extends Lint.RuleWalker {
+  public visitImportDeclaration(node: ts.ImportDeclaration): void {
+    const moduleSpecifier = node.moduleSpecifier.getText();
+    const match = moduleSpecifier.match(/^['"]rxjs(\/\w+)?\/index/);
+    if (match) {
+      this.addFailureAtNode(
+        node.moduleSpecifier,
+        "RxJS imports from index are forbidden - see https://github.com/ReactiveX/rxjs/issues/4230"
+      );
+    }
+    super.visitImportDeclaration(node);
+  }
+}

test/v6/fixtures/no-index/default/fixture.ts.lint

@@ -0,0 +1,10 @@
+import { Observable } from "rxjs/index";
+                           ~~~~~~~~~~~~                     [no-index]
+import { map } from "rxjs/operators/index";
+                    ~~~~~~~~~~~~~~~~~~~~~~                  [no-index]
+import { TestScheduler } from "rxjs/testing/index";
+                              ~~~~~~~~~~~~~~~~~~~~          [no-index]
+import { WebSocketSubject } from "rxjs/webSocket/index";
+                                 ~~~~~~~~~~~~~~~~~~~~~~     [no-index]
+
+[no-index]: RxJS imports from index are forbidden - see https://github.com/ReactiveX/rxjs/issues/4230

test/v6/fixtures/no-index/default/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "lib": ["es2015"],
+    "noEmit": true,
+    "paths": {
+      "rxjs": ["../../node_modules/rxjs"]
+    },
+    "skipLibCheck": true,
+    "target": "es5"
+  },
+  "include": ["fixture.ts"]
+}

test/v6/fixtures/no-index/default/tslint.json

@@ -0,0 +1,8 @@
+{
+  "defaultSeverity": "error",
+  "jsRules": {},
+  "rules": {
+    "rxjs-no-index": { "severity": "error" }
+  },
+  "rulesDirectory": "../../../../../build/rules"
+}