Hello World

Your First Program

Create a file called hello.ts:

// demonstrates: the minimal Perry program in the docs
// docs: docs/src/getting-started/hello-world.md
// platforms: macos, linux, windows
// targets: wasm, web, android

console.log("Hello, Perry!")

Compile and run it:

perry hello.ts -o hello
./hello

Output:

Hello, Perry!

That’s it. Perry compiled your TypeScript to a native executable — no Node.js, no bundler, no runtime.

A Slightly Bigger Example

// demonstrates: recursive fib as a perf-vs-node talking point
// docs: docs/src/getting-started/hello-world.md
// platforms: macos, linux, windows
// targets: wasm, web, android

function fibonacci(n: number): number {
    if (n <= 1) return n
    return fibonacci(n - 1) + fibonacci(n - 2)
}

const start = Date.now()
const result = fibonacci(35)
const elapsed = Date.now() - start

console.log(`fibonacci(35) = ${result}`)
console.log(`Completed in ${elapsed}ms`)

perry fib.ts -o fib
./fib

This runs about 2x faster than Node.js because Perry compiles to native machine code with integer specialization.

Using Variables and Functions

const name: string = "World"
const items: number[] = [1, 2, 3, 4, 5]

const doubled = items.map((x) => x * 2)
const sum = doubled.reduce((acc, x) => acc + x, 0)

console.log(`Hello, ${name}!`)
console.log(`Sum of doubled: ${sum}`)

Async Code

// demonstrates: async/await fetch shown in hello-world.md
// docs: docs/src/getting-started/hello-world.md
// platforms: macos, linux, windows
// run: false

async function fetchData(): Promise<string> {
    const response = await fetch("https://httpbin.org/get")
    const data = await response.json() as { origin: string }
    return data.origin
}

const ip = await fetchData()
console.log(`Your IP: ${ip}`)

perry fetch.ts -o fetch
./fetch

Perry compiles async/await to a native async runtime backed by Tokio.

Multi-Threading

Perry can do something no JavaScript runtime can — run your code on multiple CPU cores:

// demonstrates: parallelMap + spawn shown in hello-world.md
// docs: docs/src/getting-started/hello-world.md
// platforms: macos, linux, windows

import { parallelMap, parallelFilter, spawn } from "perry/thread"

const data = [1, 2, 3, 4, 5, 6, 7, 8]

// Process all elements across all CPU cores
const doubled = parallelMap(data, (x: number) => x * 2)
console.log(doubled) // [2, 4, 6, 8, 10, 12, 14, 16]

// Run heavy work in the background
const result = await spawn(() => {
    let sum = 0
    for (let i = 0; i < 100_000_000; i++) sum += i
    return sum
})
console.log(result)

// parallelFilter is also available for the lift-and-parallelize case:
const evens = parallelFilter(data, (x: number) => x % 2 === 0)
console.log(evens)

This is real OS-level parallelism, not web workers or separate isolates. See Multi-Threading for details.

What the Compiler Produces

When you run perry file.ts -o output, Perry:

Parses your TypeScript with SWC
Lowers the AST to an intermediate representation (HIR)
Applies optimizations (inlining, closure conversion, etc.)
Generates native machine code with LLVM
Links with your system’s C compiler

The result is a standalone executable with no external dependencies.

Binary Size

Program	Binary Size
Hello world	~300KB
CLI with fs/path	~3MB
UI app	~3MB
Full app with stdlib	~48MB

Perry automatically detects which runtime features you use and only links what’s needed.

Perry Documentation