[Node.JS] Open a JSON file and list each one of values of a key

list.js

#!/usr/local/bin/node

// require
var fs = require("fs");

var sourceData = fs.readFileSync("ttl.json","utf8");

sourceData = JSON.parse(sourceData);

for(const categoryName in sourceData){
	for(const currentItem of sourceData[categoryName]){
		console.log(currentItem.slug);
	}
}