Show HN: minfern – Type inference for JavaScript without transpilation(github.com)

  function calculateTotal(product, quantity) {
    return product.price * quantity;
  }
  var item = {
    name: "Wireless Mouse",
    cost: 25 // Note the property name is 'cost', not 'price'
  };
  console.log(calculateTotal(item, 2));

  Error: Property 'price' not found in type {cost: Number, name: String}
      ╭─[ tests/example_error.js:11:13 ]
      │
   11 │ console.log(calculateTotal(item, 2));
      │             ───────────┬───────────  
      │                        ╰───────────── Property 'price' not found in type {cost: Number, name: String}
  ────╯