How can I call a function in a class from a collider method when this is a different scope?

[mhcdotcom]

Hey All, I hope you can help me.
I've asked the same question on Stack overflow. I hope you don't mind using it as a reference and answering either here or there. 
https://stackoverflow.com/questions/53093928/how-can-i-call-a-function-in-a-class-from-a-collider-method-when-this-is-a-diffe

You're help is really appreciated.

Thank you.

[elleniaw]

As you can see in here: https://photonstorm.github.io/phaser3-docs/Phaser.Physics.Arcade.Factory.html#collider__anchor
the method takes a callback, but also as a last parameter it takes a context. So instead of doing this:

create(){
    this.physics.add.collider(
      this.player,
      this.bombs,
      npcs.hitBomb,
      null,
      this
    )

Do this:

create(){
    this.physics.add.collider(
      this.player,
      this.bombs,
      npcs.hitBomb,
      null,
      npcs
    )

Because now you pass a context to the callback (npcs.hitBomb) the npc's context. If you ever run into a situation where a method would not give you the possibility to pass a context you can look into .bind:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_objects/Function/bind

Lambdas are also a great way to work around it but I would not recommend that for how you want to use it (calling a method on another object)
 

 

[samme]