SMoL Tutor is a web app that corrects common misconceptions about basic concepts in modern programming languages. Specifically, the tutor teaches you, for example, how to answer the following questions:

let x = 2;
function main() {
  function getX() {
    return x;
  let y = getX();
  let x = 3;
  return y;
let x = [ 3 ];
let v = [ 1, 2, x ];
x[0] = 4;


These tutorials are hosted with Google Apps Script. We do record your work in the tutorials, but we do no record your identity.

Each tutorial typically takes 10-20 min (rarely exceeding 30 min). You can save the finished tutorials to PDF once you finish. However, you will lose your work if you close a tutorial in the middle.

Here are all tutorials.

Change since 2022