What is the difference between spawn() and fork() in Node.js?

Question

Accepted Answer

**spawn()** — new process, any executable. **fork()** — new Node.js process, IPC channel.

**spawn():**
- Creates new process.
- Can run any executable.
- No IPC channel by default.
- Streams stdout/stderr.

```javascript
const { spawn } = require("child_process");
const child = spawn("ls", ["-la"]);

child.stdout.on("data", (data) => {
    console.log(data.toString());
});
```

**fork():**
- Creates new Node.js process.
- Built on spawn().
- Has IPC channel for communication.
- Can send JSON messages.

```javascript
const { fork } = require("child_process");
const child = fork("./worker.js");

// Send message to child
child.send({ task: "compute" });

// Receive from child
child.on("message", (msg) => {
    console.log(msg);
});
```

**Key differences:**
- **spawn** — any executable, no IPC.
- **fork** — Node.js only, has IPC.
- **fork** — easier communication.

Node.js: What is the difference between spawn() and fork() in Node.js?