containsCommonItem

const array1 = ['a', 'b', 'c', 'x']
const array2 = ['z', 'y', 'a']
// if we had two empty arrays [] this would still work as in JS object properties
// are turned into strings when created

// O(a + b) time complexity
// O(a) space complexity 
function containsCommonItem(arr1, arr2) {
    // loop through first array and create object where properties === items in 
    // the array
    // can we assume always 2 params?
    let map = {}
    for (let i = 0; i < arr1.length; i++) {
        if (!map[i]) {
            const item = arr1[i]
            map[item] = true
        }
    }
    // loop through second array and check if item in second array exists on
    // created object
    for (let i = 0; i < arr2.length; i++) {
        let checkVar = map[arr2[i]]
        if (map[arr2[i]]) {
            return true
        }
    }
    return false
}

let resultVar = containsCommonItem(array1, array2)
console.log(resultVar)

// Language specific to JS
function containsCommonItem2(arr1, arr2) {
    // iterate arr1 and if arr2 includes an element presen in arr1 return true
    return arr1.some(item => arr2.include(item));
}