Premium

Implement lodash.get

By FrontendAtlas Team · Updated Jan 31, 2026

Implement get(obj, path, defaultValue) where path is a string like user.profile.name or a[0].b. Return defaultValue when the path does not exist.

What you’ll build / What this tests

This premium javascript coding focuses on Implement lodash.get. You’ll apply objects and parsing thinking with intermediate level constraints. The prompt emphasizes Implement get(obj, path, defaultValue) where path is a string like user.profile.name or a[0].b. Return defaultValue when….

Learning goals

Translate the prompt into a clear javascript API signature and return shape.
Apply objects, parsing, iteration techniques to implement implement lodash.get.
Handle intermediate edge cases without sacrificing readability.
Reason about time/space complexity and trade-offs in javascript.

Key decisions to discuss

Define the exact input/output contract before coding.
Prioritize predictable edge-case handling over micro-optimizations.

Evaluation rubric

Correctness: covers required behaviors and edge cases.
Clarity: readable structure and predictable control flow.
Complexity: avoids unnecessary work for large inputs.
API discipline: no mutation of inputs; returns expected shape.
Testability: solution is easy to unit test.

Constraints / Requirements

Handle empty strings and mixed casing without errors.
Avoid prototype pitfalls when reading object keys.
Avoid mutating nested objects; return new references.
Handle empty or missing inputs without throwing errors.
Keep runtime close to linear time where possible.
Prefer a pure function: no side effects beyond the return value.

Mini snippet (usage only)

// Example usage
const obj = /* implement lodash.get input */;
const path = /* config */;
const result = get(obj, path);
console.log(result);

// Edge case check
const empty = obj && path ?? null;
const fallback = get(obj, path);
console.log(fallback);

// Expected: describe output shape, not the implementation
// (no solution code in preview)

Common pitfalls

Mutating inputs instead of returning a new value.
Skipping edge cases like empty input, duplicates, or nulls.
Overlooking time complexity for large inputs.