Welcome to proc

Running child processes and working with streams should be simple. proc makes it simple.

✨ The Big Idea: Treat processes and streams like arrays. Use map, filter, reduce on anything. Errors flow naturally through pipelines. No callbacks, no edge cases, no headaches.

What is proc?

proc is a Deno library that gives you two superpowers:

1. Run child processes with a clean, composable API
2. Work with async iterables using the Array methods you already know

But here's the real magic: errors just work. They flow through your pipelines naturally, like data. No edge cases, no separate error channels, no callbacks. One try-catch at the end handles everything.

💡 Tip: If you've ever struggled with JavaScript streams, you're going to love this.

A Taste of proc

Count lines in a compressed file—streaming, no temp files:

import { read } from "jsr:@j50n/proc@0.23.3";

const lines = await read("war-and-peace.txt.gz")
  .transform(new DecompressionStream("gzip"))
  .lines
  .count();

console.log(`${lines} lines`); // 23,166 lines

Chain processes like shell pipes:

import { run } from "jsr:@j50n/proc@0.23.3";

const result = await run("cat", "data.txt")
  .run("grep", "error")
  .run("wc", "-l")
  .lines.first;

Handle errors gracefully:

import { run } from "jsr:@j50n/proc@0.23.3";

try {
  await run("npm", "test")
    .lines
    .map((line) => line.toUpperCase())
    .filter((line) => line.includes("FAIL"))
    .forEach((line) => console.log(line));
} catch (error) {
  // All errors caught here—from the process, from map, from filter
  console.error(`Tests failed: ${error.code}`);
}

Why proc?

JavaScript streaming is fast, but error handling shouldn't break your brain. proc gives you:

• Errors that propagate naturally through pipelines
• Array methods on async iterables (map, filter, reduce, and more)
• Process management that feels like shell scripting
• Streaming everything for memory efficiency
• Type safety with full TypeScript support

Who is this for?

• DevOps engineers automating deployments, processing logs, and managing infrastructure
• Data engineers processing large CSV files, log files, or streaming data
• Backend developers building CLI tools, batch processors, or data pipelines
• System administrators replacing Bash scripts with type-safe, testable Deno code
• Anyone who needs to run child processes or work with large datasets efficiently

Ready to dive in?

Start with Installation or jump straight to the Quick Start.

Current Version: 0.23.3
Status: Stable, actively maintained, ready for production

Found a bug? Have a question? File an issue or check the FAQ.