ScriptdrillRead a nested value by path
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
Follow a dot path like `"user.address.city"` or `"items.0.id"` (numbers index arrays) into `obj` and return the value there. If a step along the way is missing, `null` or `undefined`, or the final value is `undefined`, return `fallback`. Real values such as `0`, `false`, `""` and a final `null` are returned as they are. An empty path returns `obj`.
What this exercise teaches
Checking for null or undefined before each step prevents a TypeError on missing branches. Testing the final value with === undefined, instead of ||, keeps falsy but real values like 0, false, "" and null.
A hint if you get stuck
Split the path on `.` and walk one key at a time. Stop with `fallback` as soon as the current value is `null` or `undefined`. Avoid `||`, which also replaces `0` and `""`.
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