fix: don't require Finnish notation or Subject suffixes for forkJoin or combineLatest properties (#212)

Resolves #40

### Before
```ts
combineLatest({
  number$: of(0),
  letterSubject$: new BehaviorSubject('a')
});
```

### After 
```ts
combineLatest({
  number: of(0),
  letter: new BehaviorSubject('a')
});
```

---------

Co-authored-by: Jason Weinzierl <[email protected]>

Author: ChrisMBarr

docs/rules/finnish.md

@@ -18,6 +18,9 @@ Examples of **correct** code for this rule:
 
 ```ts
 const answer$ = of(42, 54);
+
+// The static observable creators that accept a sources object are exempt from this rule.
+combineLatest({ answer: of(42, 54) });
 ```
 
 ## Options

docs/rules/suffix-subjects.md

@@ -23,6 +23,9 @@ Examples of **correct** code for this rule:
 ```ts
 const answersSubject = new Subject<number>();
 const answersSubject$ = new Subject<number>();
+
+// The static observable creators that accept a sources object are exempt from this rule.
+combineLatest({ answers: new Subject<number>() });
 ```
 
 ## Options

src/constants.ts

@@ -1,5 +1,14 @@
 export const defaultObservable = String.raw`[Aa]ction(s|s\$|\$)$`;
 
+/**
+ * The names of static observable creators
+ * that accept a sources object as input.
+ */
+export const SOURCES_OBJECT_ACCEPTING_STATIC_OBSERVABLE_CREATORS = [
+  'combineLatest',
+  'forkJoin',
+];
+
 /**
  * The names of operators that are safe to be used after
  * operators like `takeUntil` that complete the observable.

src/rules/finnish.ts

@@ -2,8 +2,9 @@ import { AST_NODE_TYPES, TSESTree as es, ESLintUtils } from '@typescript-eslint/
 import {
   findParent,
   getLoc,
-  getTypeServices } from '../etc';
-import { ruleCreator } from '../utils';
+  getTypeServices,
+} from '../etc';
+import { isSourcesObjectAcceptingStaticObservableCreator, ruleCreator } from '../utils';
 
 const defaultOptions: readonly {
   functions?: boolean;
@@ -228,7 +229,7 @@ export const finnishRule = ruleCreator({
       ) => {
         if (validate.properties) {
           const parent = node.parent as es.Property;
-          if (node === parent.key) {
+          if (node === parent.key && !isSourcesObjectAcceptingStaticObservableCreator(parent.parent.parent)) {
             checkNode(node);
           }
         }

src/rules/suffix-subjects.ts

@@ -4,7 +4,7 @@ import {
   getLoc,
   getTypeServices,
 } from '../etc';
-import { escapeRegExp, ruleCreator } from '../utils';
+import { escapeRegExp, isSourcesObjectAcceptingStaticObservableCreator, ruleCreator } from '../utils';
 
 const defaultOptions: readonly {
   parameters?: boolean;
@@ -161,7 +161,7 @@ export const suffixSubjectsRule = ruleCreator({
       ) => {
         if (validate.properties) {
           const parent = node.parent as es.Property;
-          if (node === parent.key) {
+          if (node === parent.key && !isSourcesObjectAcceptingStaticObservableCreator(parent.parent.parent)) {
             checkNode(node);
           }
         }

src/utils/index.ts

@@ -1,4 +1,5 @@
 export * from './create-regexp-for-words';
 export * from './escape-regexp';
 export * from './find-is-last-operator-order-valid';
+export * from './is-sources-object-accepting-static-observable-creator';
 export * from './rule-creator';

src/utils/is-sources-object-accepting-static-observable-creator.ts

@@ -0,0 +1,18 @@
+import { TSESTree as es } from '@typescript-eslint/utils';
+import { SOURCES_OBJECT_ACCEPTING_STATIC_OBSERVABLE_CREATORS } from '../constants';
+import { isCallExpression, isIdentifier } from '../etc/is';
+
+/**
+ * Returns true if the given expression is a call to a
+ * sourcesObject-accepting static observable creator.
+ *
+ * @example
+ * ```ts
+ * combineLatest({ a$: of(), b$: of() });
+ * ```
+ */
+export function isSourcesObjectAcceptingStaticObservableCreator(expression: es.Node): boolean {
+  return isCallExpression(expression)
+    && isIdentifier(expression.callee)
+    && SOURCES_OBJECT_ACCEPTING_STATIC_OBSERVABLE_CREATORS.includes(expression.callee.name);
+}

tests/rules/finnish.test.ts

@@ -200,6 +200,15 @@ ruleTester({ types: true }).run('finnish', finnishRule, {
       `,
       options: [{ properties: false }],
     },
+    {
+      code: stripIndent`
+        // Static observable creators that accept a sources object
+        import { of, combineLatest, forkJoin } from "rxjs";
+
+        combineLatest({ one: of(0), two: of('a') });
+        forkJoin({ one: of(0), two: of('a') });
+      `,
+    },
   ],
   invalid: [
     fromFixture(

tests/rules/suffix-subjects.test.ts

@@ -282,6 +282,15 @@ ruleTester({ types: true }).run('suffix-subjects', suffixSubjectsRule, {
         const mySubject = new MySubject<number>();
       `,
     },
+    {
+      code: stripIndent`
+        // Static observable creators that accept a sources object
+        import { Subject, BehaviorSubject, combineLatest, forkJoin } from "rxjs";
+
+        combineLatest({ one: new Subject<number>(), two: new BehaviorSubject('a') });
+        forkJoin({ one: new Subject<number>(), two: new BehaviorSubject('a') });
+      `,
+    },
   ],
   invalid: [
     fromFixture(