AI solution for JavaScript Coding Question on BFE.dev
85. implement `_.get()`

Here's one possible implementation of a get() function:

function get(obj, path, defaultValue) {
  const keys = Array.isArray(path) ? path : path.split('.');
  let value = obj;
  for (let key of keys) {
    if (value && typeof value === 'object') {
      value = Array.isArray(value) ? value[parseInt(key)] : value[key];
    } else {
      value = undefined;
      break;
    }
  }
  return value === undefined ? defaultValue : value;
}

This implementation first checks if the path is given as an array or a string. Then it splits the path into individual keys and loops over them, checking if each key is a valid property of the value object. If it is, the value is updated to the corresponding property value. If it's not, the loop is broken and undefined is returned.

At the end, the function returns either the value if it's not undefined, or the defaultValue if it's provided.

This implementation should be able to handle the test cases provided in the prompt.