no-unreachable

Statements that follow a return, throw, break, or continue in the same block never run. Neither does code after a loop that never ends. It's either dead code you can delete, or code that was meant to run and is in the wrong place.

Function declarations and var declarations without a value are hoisted, so they aren't reported.

This rule is on by default in JavaScript files. It's off in TypeScript files, where TypeScript finds unreachable code itself.

Configure

On by default as a warning. To turn it off:

[lint.rules]
"no-unreachable" = "off" # or "error"

Examples

Reported:

function price(item) {
  return item.price * item.quantity;
  console.log("computed", item.id);
}

while (true) {
  poll();
}
cleanUp();

Not reported:

function price(item) {
  console.log("computing", item.id);
  return item.price * item.quantity;
}

function area(shape) {
  return width() * shape.height;

  function width() {
    return shape.width;
  }
}

super() creates a subclass's fields. If the constructor never calls it, the fields are reported:

class Admin extends User {
  role = "admin";

  constructor() {
    return loadAdmin();
  }
}