这里做什么递归函数？

Question

我不明白在这里的deepEqual递归调用。

我只了解递归后a和b归因于键的值，请向我解释如何！有效。

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