feat: exposing merge command

Co-authored-by: Tyera Eulberg <teulberg@gmail.com>

web3.js/src/stake-program.ts

@@ -166,6 +166,14 @@ export type DeactivateStakeParams = {
   authorizedPubkey: PublicKey;
 };
 
+/**
+ * Deactivate stake instruction params
+ */
+export type MergeStakeParams = {
+  stakePubkey: PublicKey;
+  sourceStakePubKey: PublicKey;
+  authorizedPubkey: PublicKey;
+};
 /**
  * Stake Instruction class
  */
@@ -399,7 +407,8 @@ export type StakeInstructionType =
   | 'Delegate'
   | 'Initialize'
   | 'Split'
-  | 'Withdraw';
+  | 'Withdraw'
+  | 'Merge';
 
 /**
  * An enumeration of valid stake InstructionType's
@@ -446,6 +455,15 @@ export const STAKE_INSTRUCTION_LAYOUTS: {
     index: 5,
     layout: BufferLayout.struct([BufferLayout.u32('instruction')]),
   },
+  Merge: {
+    index: 7,
+    layout: BufferLayout.struct([
+      BufferLayout.u32('instruction'),
+      Layout.publicKey('stakePubKey'),
+      Layout.publicKey('sourceStakePubKey'),
+      Layout.publicKey('authorityOwner'),
+    ]),
+  },
   AuthorizeWithSeed: {
     index: 8,
     layout: BufferLayout.struct([
@@ -706,6 +724,31 @@ export class StakeProgram {
     });
   }
 
+  /**
+   * Generate a Transaction that merges Stake accounts.
+   */
+  static merge(params: MergeStakeParams): Transaction {
+    const {stakePubkey, authorizedPubkey, sourceStakePubKey} = params;
+    const type = STAKE_INSTRUCTION_LAYOUTS.Merge;
+    const data = encodeData(type);
+
+    return new Transaction().add({
+      keys: [
+        {pubkey: stakePubkey, isSigner: false, isWritable: true},
+        {pubkey: sourceStakePubKey, isSigner: false, isWritable: true},
+        {pubkey: SYSVAR_CLOCK_PUBKEY, isSigner: false, isWritable: false},
+        {
+          pubkey: SYSVAR_STAKE_HISTORY_PUBKEY,
+          isSigner: false,
+          isWritable: false,
+        },
+        {pubkey: authorizedPubkey, isSigner: true, isWritable: false},
+      ],
+      programId: this.programId,
+      data,
+    });
+  }
+
   /**
    * Generate a Transaction that withdraws deactivated Stake tokens.
    */