Trouble creating sprite sheet from scratch

I'm trying to use sprite sheets, but the sprites just come up blank. I don't see any errors.

first I created the spritesheet data as a js object

         here is the data i used: https://pastebin.com/vJ4pUq01

then I created a spritesheet based off a base texture:
 

let spriteSheetTexture = new PIXI.BaseTexture('images/spritesheet.png');
GAME.currentMap.spritesheet = new PIXI.Spritesheet(spriteSheetTexture, GAME.spriteSheetData);

Then I created a sprite from the spritesheet:

GAME.player.sprite = new PIXI.Sprite(GAME.currentMap.spritesheet.textures['mainCollectable.png']);

The GAME.currentMap.spritesheet.textures object seems to be empty though, I don't get why.