fix(no-ignored-replay-buffer): check config bufferSize (#12)

Fixes cartant#100

There's also a proposed fix PR in the upstream repo
cartant#114 but I avoided
looking at that solution to avoid any license issue, so this solution
might be different.

- Fix: if the `shareReplay` operator was passed an object config, then
require `bufferSize` to be in that object.
- Fix: the rule wasn't handling if `shareReplay` is imported under a
namespace.
- (Might need to review the entire project. Since rxjs now recommends
importing from "rxjs" instead of "rxjs/operators", there's a risk that
many rules also fail to account for that new paradigm. Note that this
rule is the only rule that tests namespace imports for all cases, so we
at least should expand that coverage/type of test.)

Author: JasonWeinzierl

docs/rules/no-ignored-replay-buffer.md

@@ -15,6 +15,11 @@ import { ReplaySubject } from "rxjs";
 const subject = new ReplaySubject<number>();
 ```
 
+```ts
+import { of, shareReplay } from "rxjs";
+of(42).pipe(shareReplay({ refCount: true }));
+```
+
 Examples of **correct** code for this rule:
 
 ```ts
@@ -26,3 +31,8 @@ const subject = new ReplaySubject<number>(1);
 import { ReplaySubject } from "rxjs";
 const subject = new ReplaySubject<number>(Infinity);
 ```
+
+```ts
+import { of, shareReplay } from "rxjs";
+of(42).pipe(shareReplay({ refCount: true, bufferSize: 1 }));
+```

src/rules/no-ignored-replay-buffer.ts

@@ -1,4 +1,4 @@
-import { TSESTree as es } from '@typescript-eslint/utils';
+import { AST_NODE_TYPES, TSESTree as es } from '@typescript-eslint/utils';
 import { ruleCreator } from '../utils';
 
 export const noIgnoredReplayBufferRule = ruleCreator({
@@ -17,16 +17,35 @@ export const noIgnoredReplayBufferRule = ruleCreator({
   },
   name: 'no-ignored-replay-buffer',
   create: (context) => {
+    function checkShareReplayConfig(
+      node: es.Identifier,
+      shareReplayConfigArg: es.ObjectExpression,
+    ) {
+      if (!shareReplayConfigArg.properties.some(p => p.type === AST_NODE_TYPES.Property && p.key.type === AST_NODE_TYPES.Identifier && p.key.name === 'bufferSize')) {
+        context.report({
+          messageId: 'forbidden',
+          node,
+        });
+      }
+    }
+
     function checkNode(
-      node: es.Node,
-      { arguments: args }: { arguments: es.Node[] },
+      node: es.Identifier,
+      { arguments: args }: es.NewExpression | es.CallExpression,
     ) {
       if (!args || args.length === 0) {
         context.report({
           messageId: 'forbidden',
           node,
         });
       }
+
+      if (node.name === 'shareReplay' && args?.length === 1) {
+        const arg = args[0];
+        if (arg.type === AST_NODE_TYPES.ObjectExpression) {
+          checkShareReplayConfig(node, arg);
+        }
+      }
     }
 
     return {
@@ -49,6 +68,13 @@ export const noIgnoredReplayBufferRule = ruleCreator({
         const callExpression = node.parent as es.CallExpression;
         checkNode(node, callExpression);
       },
+      'CallExpression > MemberExpression > Identifier[name=/^(publishReplay|shareReplay)$/]': (
+        node: es.Identifier,
+      ) => {
+        const memberExpression = node.parent as es.MemberExpression;
+        const callExpression = memberExpression.parent as es.CallExpression;
+        checkNode(node, callExpression);
+      },
     };
   },
 });

tests/rules/no-ignored-replay-buffer.test.ts

@@ -26,6 +26,13 @@ ruleTester({ types: false }).run('no-ignored-replay-buffer', noIgnoredReplayBuff
 
       const a = of(42).pipe(shareReplay(1));
     `,
+    fromFixture(
+      stripIndent`
+        // shareReplay with config not ignored
+        import { interval, shareReplay } from "rxjs";
+        interval(1000).pipe(shareReplay({ bufferSize: 1, refCount: true }));
+      `,
+    ),
     stripIndent`
       // namespace ReplaySubject not ignored
       import * as Rx from "rxjs";
@@ -47,6 +54,13 @@ ruleTester({ types: false }).run('no-ignored-replay-buffer', noIgnoredReplayBuff
 
       const a = Rx.of(42).pipe(shareReplay(1));
     `,
+    stripIndent`
+      // namespace shareReplay with config not ignored
+      import * as Rx from "rxjs";
+      import { shareReplay } from "rxjs/operators";
+
+      const a = Rx.of(42).pipe(shareReplay({ bufferSize: 1, refCount: true }));
+    `,
     stripIndent`
       // namespace class not ignored
       import * as Rx from "rxjs";
@@ -91,6 +105,15 @@ ruleTester({ types: false }).run('no-ignored-replay-buffer', noIgnoredReplayBuff
                               ~~~~~~~~~~~ [forbidden]
       `,
     ),
+    fromFixture(
+      stripIndent`
+        // shareReplay with config ignored
+        import { of, shareReplay } from "rxjs";
+
+        const a = of(42).pipe(shareReplay({ refCount: true }));
+                              ~~~~~~~~~~~ [forbidden]
+      `,
+    ),
     fromFixture(
       stripIndent`
         // namespace ReplaySubject ignored
@@ -122,6 +145,14 @@ ruleTester({ types: false }).run('no-ignored-replay-buffer', noIgnoredReplayBuff
                                  ~~~~~~~~~~~ [forbidden]
       `,
     ),
+    fromFixture(
+      stripIndent`
+        // namespace shareReplay with config ignored
+        import * as Rx from "rxjs";
+        const a = Rx.of(42).pipe(Rx.shareReplay({ refCount: true }));
+                                    ~~~~~~~~~~~ [forbidden]
+      `,
+    ),
     fromFixture(
       stripIndent`
         // namespace class ignored