Try Online

Our Playground lets you try ReScript online, and comes with ReScript-React preinstalled.

Quickly Evaluate Code In Terminal

Use bsc -e:

SH
❯ bsc -e 'let add = (x, y) => x + y'
// Generated by ReScript, PLEASE EDIT WITH CARE
'use strict';


function add(x, y) {
  return x + y | 0;
}

exports.add = add;
/* No side effect */

You can pipe the output to Node to run it:

SH
❯ bsc -e 'let add = (x, y) => x + y; Js.log(add(1, 2))' | node
3

Quickly Compile A Single File

You can compile a file directly via bsc MyFile.res:

RES
// MyFile.res
let rec fib = n => {
  switch n {
  | 0 | 1 => n
  | n => fib(n - 1) + fib(n - 2)
  }
}
Js.log(fib(0))

SH
❯ bsc MyFile.res
// Generated by ReScript, PLEASE EDIT WITH CARE
'use strict';


function fib(n) {
  if (n === 0 || n === 1) {
    return n;
  } else {
    return fib(n - 1 | 0) + fib(n - 2 | 0) | 0;
  }
}

console.log(fib(0));

exports.fib = fib;
/*  Not a pure module */

You can also get the inferred type signatures directly via bsc -i MyFile.res

SH
❯ bsc -i MyFile.res
let fib: int => int

Note that this is for quick tests. For real projects, use our build system.

Format Code

SH
❯ bsc -format MyFile.res
let rec fib = n => {
  switch n {
  | 0 | 1 => n
  | n => fib(n - 1) + fib(n - 2)
  }
}
Js.log(fib(0))

Our editor plugins come with formatting by default.