create array taking values from another array code example

Example 1: get element of an array inside another array

let array=[[1,2,3],
           ["apple","mango","grapes"],
           [true true false]]
//to get apple =====  arrayName[class][subclass]
console.log(array[1][0])

Example 2: find new values in array based on another array apps script

// elements to filter out.
const keys = [['a','b','c']],
keySet = new Set(keys[0]),

// example data.
data = [['a',1,2],
        ['c',4,3],
        ['d',3,4]],
out = data.filter(([item0])=>!keySet.has(item0));
console.info(out);