League of Extraordinary FoundryVTT Developers•3y ago

Overriding onDropItem & onSortItem

You'd override them in your sheet class.

7 Replies

Unknown User•3y ago

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Mana•3y ago

There's no such thing as preventDefault() global function. Overriding itself prevents the normal function unless you call it.

Unknown User•3y ago

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Calego•3y ago

This is what that super thing you've seen around is for. Without the "super.whatever()", you're completely overriding the method and none of the inherited behavior will fire

Calego•3y ago

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/super

super - JavaScript | MDN

The super keyword is used to access and call functions on an object's parent.

Calego•3y ago

class MySheetClass extends ActorSheet {
  // ...

  /** Extends `activateListeners` with additional logic */
  activateListeners(html) {
    super.activateListeners(html); // effectively calling `ActorSheet`'s `activateListeners` method
    
    _someOtherMethod(html);
  }

  /** Replaces `_onDropItem` with different logic */
  _onDropItem() {
    // custom logic without the `super`
  }
}

class MySheetClass extends ActorSheet {
  // ...

  /** Extends `activateListeners` with additional logic */
  activateListeners(html) {
    super.activateListeners(html); // effectively calling `ActorSheet`'s `activateListeners` method
    
    _someOtherMethod(html);
  }

  /** Replaces `_onDropItem` with different logic */
  _onDropItem() {
    // custom logic without the `super`
  }
}

What you saw with Inventory+ and libwrapper is how modules tend to override methods in existing classes which they do not control. Inventory+ doesn't have control of the ActorSheet5e class, so it had to work around that by 'monkeypatching' the method after it's already been defined. Since you're writing a system, it's unlikely you'll need libwrapper. Systems are the first-class citizens and don't really worry much about conflicts, modules are second class and do have to worry about conflicts.

Unknown User•3y ago

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Overriding onDropItem & onSortItem