Client (Typescript)

The only difference from the last client example is that we will send a non-empty array of instruction data this time.

Recap our instruction codes:

• 0: increment
• 1: decrement
• 2: set value

If the given code is 2 (set value), a user should also pass an u32 number in the other 4 bytes after the first bytes which means the total length of the array should be 5.

Here is an example how to make the array:

var instructionData = Buffer.alloc(5, 0); // [0, 0, 0, 0, 0]

// The first byte is instruction code
instructionData.writeUint8(instructionCode, 0);

// The last 4 bytes reoresents an u32 value we want to set
instructionData.writeUInt32LE(inputValue, 1);

Our program will ignore the last 4 bytes if instruction code is 0 or 1 so I just alloc 5 bytes for every cases. You can alloc only 1 byte on cases increment, and decrement of course. The program should works the same.

A user should pass the instruction and value if the instruction is "set value". Let's modify the arguments handling at the begining of the main.

const args = process.argv.slice(2);
if (args.length < 3) {
    console.log("Uasge: <instruction code> [value] <program keypair path> <payer keypair path>");
    process.exit(1);
}
const instruct = args[0];
var instructionCode = 0;
var inputValue = 0;
switch (instruct) {
    case "increment": 
        instructionCode = 0;
        break;
    case "decrement":
        instructionCode = 1;
        break;
    case "set":
        instructionCode = 2;
        inputValue = parseInt(args[1]);
        break;
}
const program_keypair_path = (instruct === "set") ? args[2] : args[1];
const payer_keypair_path = (instruct === "set") ? args[3] : args[2];

Just a simple example without invalid arguement handling. You can do better than this one.

Check out the full code

Usage

Let's set the counter to some value, then play with the increment, and decrement to check if they work properly. Finally, we set the counter again to check set value truely works.

$ ts-node src/main.ts set 100 ../program/target/deploy/setcounter-keypair.json ~/.config/solana/id.json
Payer:  46hytJBhguswo6S8fCcVtR85HEnb9nd1hwMxFWYnSHXc
Program ID:  5RKoJE1ZwEnvGjhMG9mLgz8ARFEqHV6JfectxedmM7Rg
Sending the transaction...
Address: H1JS1dZ4do8t71XUs5g3eVjcNYLdgZhzFqiHASSPC5CE counter: 100
Success
$ ts-node src/main.ts increment ../program/target/deploy/setcounter-keypair.json ~/.config/solana/id.json
Payer:  46hytJBhguswo6S8fCcVtR85HEnb9nd1hwMxFWYnSHXc
Program ID:  5RKoJE1ZwEnvGjhMG9mLgz8ARFEqHV6JfectxedmM7Rg
Sending the transaction...
Address: H1JS1dZ4do8t71XUs5g3eVjcNYLdgZhzFqiHASSPC5CE counter: 101
Success
$ ts-node src/main.ts decrement ../program/target/deploy/setcounter-keypair.json ~/.config/solana/id.json
Payer:  46hytJBhguswo6S8fCcVtR85HEnb9nd1hwMxFWYnSHXc
Program ID:  5RKoJE1ZwEnvGjhMG9mLgz8ARFEqHV6JfectxedmM7Rg
Sending the transaction...
Address: H1JS1dZ4do8t71XUs5g3eVjcNYLdgZhzFqiHASSPC5CE counter: 100
Success
$ ts-node src/main.ts set 1234 ../program/target/deploy/setcounter-keypair.json ~/.config/solana/id.json  
Payer:  46hytJBhguswo6S8fCcVtR85HEnb9nd1hwMxFWYnSHXc
Program ID:  5RKoJE1ZwEnvGjhMG9mLgz8ARFEqHV6JfectxedmM7Rg
Sending the transaction...
Address: H1JS1dZ4do8t71XUs5g3eVjcNYLdgZhzFqiHASSPC5CE counter: 1234
Success