feat(deep-operators): Add rule.

Author: cartant

README.md

@@ -73,15 +73,16 @@ The package includes the following rules (none of which are enabled by default):
 | Rule | Description | Options |
 | --- | --- | --- |
 | `rxjs-add` | Enforces the importation of patched observables and operators used in the module. | [See below](#rxjs-add) |
+| `rxjs-deep-operators` | Enforces deep importation from within `rxjs/operators` - e.g. `rxjs/operators/map`. Until Webpack does not require configuration for tree shaking to work, there will be situations where deep imports are preferred. | None |
 | `rxjs-finnish` | Enforces the use of [Finnish notation](https://medium.com/@benlesh/observables-and-finnish-notation-df8356ed1c9b). | [See below](#rxjs-finnish) |
 | `rxjs-no-add` | Disallows the importation of patched observables and operators. | [See below](#rxjs-no-add) |
 | `rxjs-no-create` | Disallows the calling of `Observable.create`. Useful as a warning. | None |
-| `rxjs-no-deep-operators` | Disallows deep importation from 'rxjs/operators'. Deep imports won't be in available in RxJS v6. | None |
+| `rxjs-no-deep-operators` | Disallows deep importation from `rxjs/operators`. Deep imports won't be in available in RxJS v6. | None |
 | `rxjs-no-do` | I do without `do` operators. [Do you not?](https://youtu.be/spG-Yj0zEyc) Well, `do` isn't always a code smell, but this rule can be useful as a warning. | None |
 | `rxjs-no-finnish` | Disallows the use of [Finnish notation](https://medium.com/@benlesh/observables-and-finnish-notation-df8356ed1c9b). | None |
 | `rxjs-no-ignored-error` | Disallows the calling of `subscribe` without specifying an error handler. | None |
 | `rxjs-no-ignored-subscribe` | Disallows the calling of subscribe without specifying arguments. | None |
-| `rxjs-no-operator` | Disallows importation from 'rxjs/operator'. Useful if you prefer ['lettable' operators](https://github.com/ReactiveX/rxjs/blob/master/doc/lettable-operators.md) - which are located in the `operators` directory. | None |
+| `rxjs-no-operator` | Disallows importation from `rxjs/operator`. Useful if you prefer ['lettable' operators](https://github.com/ReactiveX/rxjs/blob/master/doc/lettable-operators.md) - which are located in the `operators` directory. | None |
 | `rxjs-no-patched` | Disallows the calling of patched methods. Methods must be imported and called explicitly - not via `Observable` or `Observable.prototype`. | [See below](#rxjs-no-add) |
 | `rxjs-no-subject-unsubscribe` | Disallows calling the `unsubscribe` method of a `Subject` instance. For an explanation of why this can be a problem, see [this](https://stackoverflow.com/a/45112125/6680611) Stack Overflow answer. | None |
 | `rxjs-no-subject-value` | Disallows accessing the `value` property of a `BehaviorSubject` instance. | None |

docs/index.md

@@ -13,15 +13,16 @@ The package includes the following rules (none of which are enabled by default):
 | Rule | Description | Options |
 | --- | --- | --- |
 | `rxjs-add` | Enforces the importation of patched observables and operators used in the module. | [See below](#rxjs-add) |
+| `rxjs-deep-operators` | Enforces deep importation from within `rxjs/operators` - e.g. `rxjs/operators/map`. Until Webpack does not require configuration for tree shaking to work, there will be situations where deep imports are preferred. | None |
 | `rxjs-finnish` | Enforces the use of [Finnish notation](https://medium.com/@benlesh/observables-and-finnish-notation-df8356ed1c9b). | [See below](#rxjs-finnish) |
 | `rxjs-no-add` | Disallows the importation of patched observables and operators. | [See below](#rxjs-no-add) |
 | `rxjs-no-create` | Disallows the calling of `Observable.create`. Useful as a warning. | None |
-| `rxjs-no-deep-operators` | Disallows deep importation from 'rxjs/operators'. Deep imports won't be in available in RxJS v6. | None |
+| `rxjs-no-deep-operators` | Disallows deep importation from `rxjs/operators`. Deep imports won't be in available in RxJS v6. | None |
 | `rxjs-no-do` | I do without `do` operators. [Do you not?](https://youtu.be/spG-Yj0zEyc) Well, `do` isn't always a code smell, but this rule can be useful as a warning. | None |
 | `rxjs-no-finnish` | Disallows the use of [Finnish notation](https://medium.com/@benlesh/observables-and-finnish-notation-df8356ed1c9b). | None |
 | `rxjs-no-ignored-error` | Disallows the calling of `subscribe` without specifying an error handler. | None |
 | `rxjs-no-ignored-subscribe` | Disallows the calling of subscribe without specifying arguments. | None |
-| `rxjs-no-operator` | Disallows importation from 'rxjs/operator'. Useful if you prefer ['lettable' operators](https://github.com/ReactiveX/rxjs/blob/master/doc/lettable-operators.md) - which are located in the `operators` directory. | None |
+| `rxjs-no-operator` | Disallows importation from `rxjs/operator`. Useful if you prefer ['lettable' operators](https://github.com/ReactiveX/rxjs/blob/master/doc/lettable-operators.md) - which are located in the `operators` directory. | None |
 | `rxjs-no-patched` | Disallows the calling of patched methods. Methods must be imported and called explicitly - not via `Observable` or `Observable.prototype`. | [See below](#rxjs-no-add) |
 | `rxjs-no-subject-unsubscribe` | Disallows calling the `unsubscribe` method of a `Subject` instance. For an explanation of why this can be a problem, see [this](https://stackoverflow.com/a/45112125/6680611) Stack Overflow answer. | None |
 | `rxjs-no-subject-value` | Disallows accessing the `value` property of a `BehaviorSubject` instance. | None |

fixtures/deep-operators/fixture.ts

@@ -0,0 +1,2 @@
+import { Observable } from "rxjs";
+import { map, tap } from "rxjs/operators";

fixtures/deep-operators/tsconfig.json

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

fixtures/deep-operators/tslint.json

@@ -0,0 +1,8 @@
+{
+  "defaultSeverity": "error",
+  "jsRules": {},
+  "rules": {
+    "rxjs-deep-operators": { "severity": "error" }
+  },
+  "rulesDirectory": "../../build/rules"
+}

source/fixtures-spec.ts

@@ -201,6 +201,17 @@ describe("fixtures", function (): void {
             });
         });
 
+        describe("deep-operators", () => {
+
+            it("should effect 'rxjs-deep-operators' errors", () => {
+
+                const result = lint("deep-operators", "tslint.json");
+
+                expect(result).to.have.property("errorCount", 1);
+                result.failures.forEach(failure => expect(failure).to.have.property("ruleName", "rxjs-deep-operators"));
+            });
+        });
+
         describe("elsewhere-with-file", () => {
 
             it("should effect an 'rxjs-add' error", () => {

source/rules/rxjsDeepOperatorsRule.ts

@@ -0,0 +1,41 @@
+/**
+ * @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 = {
+        description: "Enforces deep importation from within 'rxjs/operators'.",
+        options: null,
+        optionsDescription: "Not configurable.",
+        requiresTypeInfo: false,
+        ruleName: "rxjs-deep-operators",
+        type: "functionality",
+        typescriptOnly: false
+    };
+
+    public static FAILURE_STRING = "Deep importation from 'rxjs/operators' is required";
+
+    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();
+
+        if (/^['"]rxjs\/operators\/?['"]$/.test(moduleSpecifier)) {
+            this.addFailureAtNode(node, Rule.FAILURE_STRING);
+        }
+
+        super.visitImportDeclaration(node);
+    }
+}