Comment by auxiliarymoose

The article discusses how that turns into an infinite loop and causes a hang.

When you subtract a small float from a very large float, the value doesn't change. This is because the "steps" between float values increase with the size of the value (i.e. floats have coarser resolution for larger magnitudes)

To see this in action, try running the following in a JavaScript interpreter:

console.log(1_000_000_000_000_000_000 - 1);