Add a batch instruction helper to the JS client

clients/js/src/batch.ts

@@ -0,0 +1,64 @@
+import { AccountMeta, Address, Instruction, InstructionWithData, ReadonlyUint8Array } from '@solana/kit';
+import {
+    BATCH_DISCRIMINATOR,
+    BatchInstruction as GeneratedBatchInstruction,
+    getBatchInstruction as generatedGetBatchInstruction,
+    parseBatchInstruction as generatedParseBatchInstruction,
+    ParsedBatchInstruction,
+    ParsedToken2022Instruction,
+    parseToken2022Instruction,
+    TOKEN_2022_PROGRAM_ADDRESS,
+} from './generated';
+
+declare const nonBatchable: '__non_batchable:@solana-program/token-2022';
+
+type BatchableInstruction<TProgramAddress extends string = string> = Instruction<TProgramAddress> & {
+    readonly [nonBatchable]?: never;
+};
+
+export type BatchInstruction<
+    TProgram extends string = typeof TOKEN_2022_PROGRAM_ADDRESS,
+    TRemainingAccounts extends readonly AccountMeta<string>[] = [],
+> = GeneratedBatchInstruction<TProgram, TRemainingAccounts> & { readonly [nonBatchable]: true };
+
+export function getBatchInstruction<TProgramAddress extends Address = typeof TOKEN_2022_PROGRAM_ADDRESS>(
+    instructions: BatchableInstruction<TProgramAddress>[],
+    config?: { programAddress?: TProgramAddress },
+): BatchInstruction<TProgramAddress, AccountMeta<string>[]> {
+    const programAddress = config?.programAddress ?? TOKEN_2022_PROGRAM_ADDRESS;
+    const hasNestedBatchInstruction = instructions.some(
+        instruction => instruction.programAddress === programAddress && instruction.data?.[0] === BATCH_DISCRIMINATOR,
+    );
+    if (hasNestedBatchInstruction) {
+        throw new Error('Batch instructions cannot be nested within other batch instructions.');
+    }
+
+    const accounts = instructions.flatMap(instruction => instruction.accounts ?? []);
+    const data = instructions.map(instruction => ({
+        numberOfAccounts: instruction.accounts?.length ?? 0,
+        instructionData: instruction.data ?? new Uint8Array(),
+    }));
+
+    return Object.freeze({
+        ...generatedGetBatchInstruction<TProgramAddress>({ data }, config),
+        accounts,
+    }) as BatchInstruction<TProgramAddress, AccountMeta<string>[]>;
+}
+
+export function parseBatchInstruction<TProgram extends string>(
+    instruction: Instruction<TProgram> & InstructionWithData<ReadonlyUint8Array>,
+): ParsedBatchInstruction<TProgram> & { instructions: ParsedToken2022Instruction<TProgram>[] } {
+    const rawBatchInstruction = generatedParseBatchInstruction(instruction);
+    let accountOffset = 0;
+    const instructions = rawBatchInstruction.data.data.map(({ numberOfAccounts, instructionData }) => {
+        const innerInstruction = parseToken2022Instruction<TProgram>({
+            programAddress: instruction.programAddress,
+            data: instructionData,
+            accounts: instruction.accounts?.slice(accountOffset, accountOffset + numberOfAccounts) ?? [],
+        });
+        accountOffset += numberOfAccounts;
+        return innerInstruction;
+    });
+
+    return { ...rawBatchInstruction, instructions };
+}

clients/js/src/index.ts

@@ -1,5 +1,8 @@
 export * from './generated';
 
+// Generated overrides (must be re-exported explicitly).
+export { type BatchInstruction, getBatchInstruction, parseBatchInstruction } from './batch';
+
 export * from './amountToUiAmount';
 export * from './getInitializeInstructionsForExtensions';
 export * from './getTokenSize';