Currently delving into the world of Javascript, I encountered a coding exercise involving a "deepEqual" function that I attempted to write but ultimately struggled with. Even after reviewing the solution, one particular part perplexed me - the for loop, especially the !deepEqual(a[key], b[key])) segment. My confusion lies in why I cannot simply use (keysA[key] !== keysB[key]) or (a[key] !== b[key]). To me, it seems like the code is saying "if the values of the keys in objects a and b are not found in deepEqual, then return false," despite knowing that the values do exist. I fail to see where the actual comparison between these values takes place. Undoubtedly, my interpretation is flawed, so I am seeking clarification.
function deepEqual(a, b) {
if (a === b) return true;
if (a == null || typeof a != "object" ||
b == null || typeof b != "object") return false;
let keysA = Object.keys(a), keysB = Object.keys(b);
if (keysA.length != keysB.length) return false;
for (let key of keysA) {
if (!keysB.includes(key) || !deepEqual(a[key], b[key])) return false;
}
return true;
}
let obj = {here: {is: "an"}, object: 2};
console.log(deepEqual(obj, obj));
// → true
console.log(deepEqual(obj, {here: 1, object: 2}));
// → false
console.log(deepEqual(obj, {here: {is: "an"}, object: 2}));
// → true