feat(throw-error)!: stop linting throw statements (#22)

- Resolves #21 . Removes functionality that was linting regular js
`throw` statements. Users should prefer
https://typescript-eslint.io/rules/only-throw-error/ instead.
- Added options to disallow `any` and `unknown` if users want stricter
checking.
- Moved the report node to the return body of the factory instead of the
whole function itself.
- Reworked tests to prioritize testing passing a factory function to
`throwError` instead of a raw value, because rxjs has deprecated the
latter.

Author: JasonWeinzierl

README.md

@@ -106,6 +106,6 @@ The package includes the following rules.
 | [no-unsafe-takeuntil](docs/rules/no-unsafe-takeuntil.md)               | Disallow applying operators after `takeUntil`.                                                       | ✅  |    |    | 💭 |    |
 | [prefer-observer](docs/rules/prefer-observer.md)                       | Disallow passing separate handlers to `subscribe` and `tap`.                                         |    | 🔧 | 💡 | 💭 |    |
 | [suffix-subjects](docs/rules/suffix-subjects.md)                       | Enforce the use of a suffix in subject identifiers.                                                  |    |    |    | 💭 |    |
-| [throw-error](docs/rules/throw-error.md)                               | Enforce passing only `Error` values to error notifications.                                          |    |    |    | 💭 |    |
+| [throw-error](docs/rules/throw-error.md)                               | Enforce passing only `Error` values to `throwError`.                                                 |    |    |    | 💭 |    |
 
 <!-- end auto-generated rules list -->

docs/rules/throw-error.md

@@ -1,49 +1,38 @@
-# Enforce passing only `Error` values to error notifications (`rxjs-x/throw-error`)
+# Enforce passing only `Error` values to `throwError` (`rxjs-x/throw-error`)
 
 💭 This rule requires [type information](https://typescript-eslint.io/linting/typed-linting).
 
 <!-- end auto-generated rule header -->
 
-This rule forbids throwing values that are neither `Error` nor `DOMException` instances.
+This rule forbids passing values that are not `Error` objects to `throwError`.
+It's similar to the typescript-eslint [`only-throw-error`](https://typescript-eslint.io/rules/only-throw-error/) rule,
+but is for the `throwError` Observable creation function - not `throw` statements.
 
 ## Rule details
 
 Examples of **incorrect** code for this rule:
 
-```ts
-throw "Kaboom!";
-```
-
 ```ts
 import { throwError } from "rxjs";
-throwError("Kaboom!");
-```
 
-```ts
-import { throwError } from "rxjs";
 throwError(() => "Kaboom!");
 ```
 
 Examples of **correct** code for this rule:
 
 ```ts
-throw new Error("Kaboom!");
-```
+import { throwError } from "rxjs";
 
-```ts
-throw new RangeError("Kaboom!");
+throwError(() => new Error("Kaboom!"));
 ```
 
-```ts
-throw new DOMException("Kaboom!");
-```
+## Options
 
-```ts
-import { throwError } from "rxjs";
-throwError(new Error("Kaboom!"));
-```
+<!-- begin auto-generated rule options list -->
 
-```ts
-import { throwError } from "rxjs";
-throwError(() => new Error("Kaboom!"));
-```
+| Name                   | Description                                                 | Type    | Default |
+| :--------------------- | :---------------------------------------------------------- | :------ | :------ |
+| `allowThrowingAny`     | Whether to always allow throwing values typed as `any`.     | Boolean | `true`  |
+| `allowThrowingUnknown` | Whether to always allow throwing values typed as `unknown`. | Boolean | `true`  |
+
+<!-- end auto-generated rule options list -->

src/rules/throw-error.ts

@@ -4,54 +4,86 @@ import ts from 'typescript';
 import { couldBeFunction, couldBeType, getTypeServices } from '../etc';
 import { ruleCreator } from '../utils';
 
+const defaultOptions: readonly {
+  allowThrowingAny?: boolean;
+  allowThrowingUnknown?: boolean;
+}[] = [];
+
 export const throwErrorRule = ruleCreator({
-  defaultOptions: [],
+  defaultOptions,
   meta: {
     docs: {
       description:
-        'Enforce passing only `Error` values to error notifications.',
+        'Enforce passing only `Error` values to `throwError`.',
       requiresTypeChecking: true,
     },
     messages: {
-      forbidden: 'Passing non-Error values are forbidden.',
+      forbidden: 'Passing non-Error values is forbidden.',
     },
-    schema: [],
+    schema: [
+      {
+        properties: {
+          allowThrowingAny: { type: 'boolean', default: true, description: 'Whether to always allow throwing values typed as `any`.' },
+          allowThrowingUnknown: { type: 'boolean', default: true, description: 'Whether to always allow throwing values typed as `unknown`.' },
+        },
+        type: 'object',
+      },
+    ],
     type: 'problem',
   },
   name: 'throw-error',
   create: (context) => {
     const { esTreeNodeToTSNodeMap, program, getTypeAtLocation } = ESLintUtils.getParserServices(context);
     const { couldBeObservable } = getTypeServices(context);
+    const [config = {}] = context.options;
+    const { allowThrowingAny = true, allowThrowingUnknown = true } = config;
 
-    function checkNode(node: es.Node) {
+    function checkThrowArgument(node: es.Node) {
       let type = getTypeAtLocation(node);
+      let reportNode = node;
+
       if (couldBeFunction(type)) {
+        reportNode = (node as es.ArrowFunctionExpression).body ?? node;
+
         const tsNode = esTreeNodeToTSNodeMap.get(node);
         const annotation = (tsNode as ts.ArrowFunction).type;
         const body = (tsNode as ts.ArrowFunction).body;
         type = program.getTypeChecker().getTypeAtLocation(annotation ?? body);
       }
-      if (
-        !tsutils.isIntrinsicAnyType(type)
-        && !tsutils.isIntrinsicUnknownType(type)
-        && !couldBeType(type, /^(Error|DOMException)$/)
-      ) {
-        context.report({
-          messageId: 'forbidden',
-          node,
-        });
+
+      if (allowThrowingAny && tsutils.isIntrinsicAnyType(type)) {
+        return;
+      }
+
+      if (allowThrowingUnknown && tsutils.isIntrinsicUnknownType(type)) {
+        return;
+      }
+
+      if (couldBeType(type, /^Error$/)) {
+        return;
+      }
+
+      context.report({
+        messageId: 'forbidden',
+        node: reportNode,
+      });
+    }
+
+    function checkNode(node: es.CallExpression) {
+      if (couldBeObservable(node)) {
+        const [arg] = node.arguments;
+        if (arg) {
+          checkThrowArgument(arg);
+        }
       }
     }
 
     return {
-      'ThrowStatement > *': checkNode,
       'CallExpression[callee.name=\'throwError\']': (node: es.CallExpression) => {
-        if (couldBeObservable(node)) {
-          const [arg] = node.arguments;
-          if (arg) {
-            checkNode(arg);
-          }
-        }
+        checkNode(node);
+      },
+      'CallExpression[callee.property.name=\'throwError\']': (node: es.CallExpression) => {
+        checkNode(node);
       },
     };
   },