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A JavaScript exercise from Scriptdrill. Solve it with a code editor in your browser that runs your function against example and hidden tests, and it is checked the moment you submit.
The task
Return a new object combining `base` and `override`. When both sides hold a plain object (made with `{}`) under the same key, merge those recursively. Anything else from `override` (arrays, dates, numbers, `null`) replaces what `base` had. Do not change either input.
What this exercise teaches
Spreading base gives a fresh top-level copy, and recursion builds fresh copies of every nested object it merges, so neither input is touched. The plain-object test keeps arrays, Dates and null as whole values.
A hint if you get stuck
Start from `{ ...base }`, then go through the entries of `override`. Recurse only when both values are plain objects: `Object.getPrototypeOf(v) === Object.prototype`.
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