Add getDefaultCommitmentRequestTransformer helper

.changeset/pretty-worms-taste.md

@@ -0,0 +1,5 @@
+---
+'@solana/rpc-transformers': patch
+---
+
+Add `getDefaultCommitmentRequestTransformer` helper

packages/rpc-transformers/README.md

@@ -14,4 +14,17 @@
 
 # @solana/rpc-transformers
 
-TODO
+## Functions
+
+### `getDefaultCommitmentTransformer(config)`
+
+Creates a transformer that adds the provided default commitment to the configuration object of the request when applicable.
+
+```ts
+import { getDefaultCommitmentTransformer, OPTIONS_OBJECT_POSITION_BY_METHOD } from '@solana/rpc-transformers';
+
+const requestTransformer = getDefaultCommitmentTransformer({
+    defaultCommitment: 'confirmed',
+    optionsObjectPositionByMethod: OPTIONS_OBJECT_POSITION_BY_METHOD,
+});
+```

packages/rpc-transformers/src/__tests__/params-transformer-test.ts

@@ -2,7 +2,7 @@ import type { RpcRequestTransformer } from '@solana/rpc-spec';
 import type { Commitment } from '@solana/rpc-types';
 
 import { getDefaultRequestTransformerForSolanaRpc } from '../params-transformer';
-import { OPTIONS_OBJECT_POSITION_BY_METHOD } from '../params-transformer-options-object-position-config';
+import { OPTIONS_OBJECT_POSITION_BY_METHOD } from '../request-transformer-options-object-position-config';
 
 describe('getDefaultRequestTransformerForSolanaRpc', () => {
     describe('given no config', () => {

packages/rpc-transformers/src/__tests__/default-commitment-test.ts → packages/rpc-transformers/src/__tests__/request-transformer-default-commitment-test.ts

@@ -1,6 +1,6 @@
 import type { Commitment } from '@solana/rpc-types';
 
-import { applyDefaultCommitment } from '../default-commitment';
+import { applyDefaultCommitment } from '../request-transformer-default-commitment';
 
 const MOCK_COMMITMENT_PROPERTY_NAME = 'commitmentProperty';
 

packages/rpc-transformers/src/index.ts

@@ -1,8 +1,8 @@
-export * from './default-commitment';
 export * from './params-transformer';
 export * from './params-transformer-bigint-downcast';
 export * from './params-transformer-integer-overflow';
-export * from './params-transformer-options-object-position-config';
+export * from './request-transformer-default-commitment';
+export * from './request-transformer-options-object-position-config';
 export * from './response-transformer';
 export * from './response-transformer-allowed-numeric-values';
 export * from './response-transformer-bigint-upcast';

packages/rpc-transformers/src/params-transformer.ts

@@ -2,10 +2,10 @@ import { pipe } from '@solana/functional';
 import { RpcRequest, RpcRequestTransformer } from '@solana/rpc-spec';
 import { Commitment } from '@solana/rpc-types';
 
-import { applyDefaultCommitment } from './default-commitment';
 import { downcastNodeToNumberIfBigint } from './params-transformer-bigint-downcast';
 import { getIntegerOverflowNodeVisitor } from './params-transformer-integer-overflow';
-import { OPTIONS_OBJECT_POSITION_BY_METHOD } from './params-transformer-options-object-position-config';
+import { getDefaultCommitmentRequestTransformer } from './request-transformer-default-commitment';
+import { OPTIONS_OBJECT_POSITION_BY_METHOD } from './request-transformer-options-object-position-config';
 import { getTreeWalker, KeyPath } from './tree-traversal';
 
 export type RequestTransformerConfig = Readonly<{
@@ -28,23 +28,11 @@ export function getDefaultRequestTransformerForSolanaRpc(config?: RequestTransfo
             keyPath: [],
         };
         const patchedRequest = { methodName, params: traverse(rawParams, initialState) as T };
-        if (!Array.isArray(patchedRequest.params)) {
-            return patchedRequest;
-        }
-        const optionsObjectPositionInParams = OPTIONS_OBJECT_POSITION_BY_METHOD[methodName];
-        if (optionsObjectPositionInParams == null) {
-            return patchedRequest;
-        }
         return pipe(
             patchedRequest,
-            ({ methodName, params }) => ({
-                methodName,
-                params: applyDefaultCommitment({
-                    commitmentPropertyName: methodName === 'sendTransaction' ? 'preflightCommitment' : 'commitment',
-                    optionsObjectPositionInParams,
-                    overrideCommitment: defaultCommitment,
-                    params: params as unknown[],
-                }),
+            getDefaultCommitmentRequestTransformer({
+                defaultCommitment,
+                optionsObjectPositionByMethod: OPTIONS_OBJECT_POSITION_BY_METHOD,
             }),
             // FIXME Remove when https://github.com/anza-xyz/agave/pull/483 is deployed.
             ({ methodName, params }) => ({

packages/rpc-transformers/src/default-commitment.ts → packages/rpc-transformers/src/request-transformer-default-commitment.ts

@@ -1,18 +1,50 @@
+import type { RpcRequest, RpcRequestTransformer } from '@solana/rpc-spec';
 import type { Commitment } from '@solana/rpc-types';
 
-type Config = Readonly<{
-    commitmentPropertyName: string;
-    optionsObjectPositionInParams: number;
-    overrideCommitment?: Commitment;
-    params: unknown[];
-}>;
+export function getDefaultCommitmentRequestTransformer({
+    defaultCommitment,
+    optionsObjectPositionByMethod,
+}: Readonly<{
+    defaultCommitment?: Commitment;
+    optionsObjectPositionByMethod: Record<string, number>;
+}>): RpcRequestTransformer {
+    return <TParams>(request: RpcRequest<TParams>): RpcRequest => {
+        const { params, methodName } = request;
+
+        // We only apply default commitment to array parameters.
+        if (!Array.isArray(params)) {
+            return request;
+        }
+
+        // Find the position of the options object in the parameters and abort if not found.
+        const optionsObjectPositionInParams = optionsObjectPositionByMethod[methodName];
+        if (optionsObjectPositionInParams == null) {
+            return request;
+        }
+
+        return Object.freeze({
+            methodName,
+            params: applyDefaultCommitment({
+                commitmentPropertyName: methodName === 'sendTransaction' ? 'preflightCommitment' : 'commitment',
+                optionsObjectPositionInParams,
+                overrideCommitment: defaultCommitment,
+                params,
+            }),
+        });
+    };
+}
 
 export function applyDefaultCommitment({
     commitmentPropertyName,
     params,
     optionsObjectPositionInParams,
     overrideCommitment,
-}: Config) {
+}: Readonly<{
+    commitmentPropertyName: string;
+    optionsObjectPositionInParams: number;
+    overrideCommitment?: Commitment;
+    params: unknown[];
+}>) {
     const paramInTargetPosition = params[optionsObjectPositionInParams];
     if (
         // There's no config.