parameters.md

Parameters

• This section is about the parameters passed to a createClass factory function. The parameters you declare in your factory function are what you must pass when using the reactive class via the new keyword or the useInstance hook.
• Parameters are not reactive if you never re-assign them. There's nothing to react to, in this case, because parameters aren't implicitly updated when useInstance is called with new values.
• If anywhere in your factory function you re-assign a parameter, the compiler notices and will make it deeply reactive by default. In this sense, a parameter behaves identically to a variable.

Live parameters

• If you want a parameter to update when useInstance is called with new values, you must explicitly make it live.
• To make a parameter live, use the onUpdate function like so:

const Counter = createClass((options: CounterOptions) => {
  onUpdate<typeof Counter>(newOptions => {
    Object.assign(options, newOptions)
  })
  return {
    /* ... */
  }
})