Tish - Native Performance, Familiar Syntax

Named functions

fn add(a, b) {
    return a + b
}
 
fn double(x) = x * 2   // single-expression, implicit return

Both fn and function are supported.

Arrow functions

// Single param, expression body
let doubled = nums.map(x => x * 2)
 
// Multiple params
let sum = nums.reduce((acc, x) => acc + x, 0)
 
// No params
let getHello = () => "Hello"
 
// Block body
let process = (x) => {
    let y = x * 2
    return y + 1
}

Note: Arrow functions work in interpreter mode. Compiler mode may require named functions for some use cases.

Rest parameters

fn sum(...args) {
    let total = 0
    for (let x of args) total += x
    return total
}

Closures

Functions capture variables by name with lexical scope:

fn makeCounter() {
    let count = 0
    fn inc() {
        count++
        return count
    }
    return inc
}

Async functions

Use async fn to declare asynchronous functions that can use await:

async fn fetchData(url) {
    let res = await fetchAsync(url)
    return res.ok ? res.body : null
}
 
async fn main() {
    let data = await fetchData("https://api.example.com/data")
    console.log(data)
}
 
main()

await pauses until the Promise settles. Use with fetchAsync, fetchAllAsync, or any Promise (requires the http feature).

No `this`