Basic Data Structures (Objects, Maps, Sets) Questions
Understand how objects work in JavaScript including prototypal inheritance and property descriptors. Know when to use Maps vs Objects and Sets vs Arrays. Understand the performance characteristics of different data structures. Be comfortable with nested data structures and how to manipulate them efficiently.
HardSystem Design
0 practiced
Design an in-memory and hybrid cache for storing and serving dense vector embeddings in a Node.js-based AI service. Requirements: support 10M embeddings of 512 floats, low-latency lookup (<5ms), eviction strategy, persistence across restarts, and minimal GC pressure. Discuss Map vs typed buffers vs memory-mapped files vs external vector DBs and provide rough memory estimates and eviction options.
HardSystem Design
0 practiced
Design a lifecycle management strategy for JavaScript wrapper objects that own native GPU memory (e.g., tensors). Show how WeakRef and FinalizationRegistry could be used to release native buffers when JS wrappers are GC'd, discuss race conditions, and propose explicit APIs to ensure timely release without relying solely on garbage collection.
EasyTechnical
0 practiced
Explain JavaScript property descriptors: data descriptor attributes (value, writable, enumerable, configurable) and accessor descriptors (get/set). Show how you would make an object's property effectively read-only while still allowing other properties to be added elsewhere.
MediumTechnical
0 practiced
Implement mergeDeep(target, source) in JavaScript that recursively merges nested plain objects from source into target. Arrays should be replaced entirely (not concatenated). The function should not mutate the source; mutating target is acceptable. Explain edge cases you consider.
EasyTechnical
0 practiced
How do you iterate over all of an object's own property keys, including non-enumerable properties and Symbol keys, in JavaScript? Provide code examples and explain differences between Object.keys, Object.getOwnPropertyNames, Object.getOwnPropertySymbols, and Reflect.ownKeys.
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