I have two sample arrays below.
let arr1 = [
{ key: "WIHUGDYVWJ", className: "science" },
{ key: "qwljdhkuqwdnqwdk", className: "english" },
{ key: "likubqwd", className: "robotics" }
];
let arr2 = [
{ key: "WIHUGDYVWJ", title: "math" },
{ key: "qwljdhkuqwdnqwdk", title: "english" },
{ key: "likubqwd", title: "robotics" }
];
How can I filter arr1 to get only items that have 'className' value that matches arr2's item's 'title' value? (expecting only items with 'english' and 'robotics' to remain)
How can I filter arr1 to get only items that have 'className' value that do not match arr2's item's 'title' value? (expecting only items with 'science' to remain)
Thanks!
let arr1 = [
{ key: "WIHUGDYVWJ", className: "science" },
{ key: "qwljdhkuqwdnqwdk", className: "english" },
{ key: "likubqwd", className: "robotics" },
{ key: "abcd", className: "history" }
];
let arr2 = [
{ key: "WIHUGDYVWJ", title: "math" },
{ key: "qwljdhkuqwdnqwdk", title: "english" },
{ key: "likubqwd", title: "robotics" }
];
// q1 answer
console.log(arr1.map(arr1Item => arr2.filter(arr2Item => arr1Item.className === arr2Item.title)).flat());
// q2 answer
console.log(arr1.filter(arr1Item => !arr2.some(arr2Item => arr2Item.title === arr1Item.className)));i wrote without using a for, if/else statement as much as possible.
this code may not be the best. i think it could be more improved.
I hope my answer is helpful