JavaScript Abort Signals and Request Ownership
Learn AbortController step by step: cancel fetch, prevent stale search results, combine cancellation with timeouts and handle errors correctly.
~9 min readread →
Developer interview notes & guides — Page 22
Focused explanations and longer guides, with worked scenarios, common mistakes and interview exercises across every chapter.
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Showing 505–528 of 825 articles
JavaScript Array Copies and Shared Objects
Why a spread or slice copy of a JavaScript array still shares its nested objects, and how to pick shallow, structured or targeted copies.
~2 min readread →
JavaScript reduce(): Initial Value, Accumulator and Mutation
How Array.prototype.reduce works, why the initial value matters for empty arrays, and when mutating the accumulator is safe or quadratic.
~8 min readread →
Async/Await in Loops: forEach vs for...of vs Promise.all
Why await inside forEach does not wait, how for...of runs tasks in sequence, and how to run async work in parallel with a concurrency limit.
~7 min readread →
JavaScript Equality: Object Identity and Coercion
How === and == really compare JavaScript values: type coercion rules, why two equal-looking objects are not equal, and how to compare contents.
~2 min readread →
JavaScript Event Delegation and Dynamic Elements
Handle clicks on dynamic list items with one listener: how JavaScript event delegation works, closest(), stopPropagation traps and testing.
~2 min readread →
JavaScript Object.freeze: Shallow vs Deep Freeze and Limits
What Object.freeze really locks, why it is shallow, how strict mode changes failures, and how to deep freeze config without surprises.
~7 min readread →
JavaScript Generators: return(), finally and Cleanup on Early Exit
How break, return and throw end a generator early, why finally blocks run on cleanup, and how to avoid leaking handles in iterators.
~6 min readread →
JavaScript Iterator Protocol: Make Any Object Iterable
How Symbol.iterator, next() and done power for...of and spread, how to make a class iterable, and why iterators are usually single-use.
~6 min readread →
JavaScript Map vs Object: When to Use Each (Interview Answer)
Map vs plain object for lookups: key types, insertion order, size, prototype keys like __proto__, JSON support and performance trade-offs.
~6 min readread →
JavaScript Memory Leaks and Retained References
Find JavaScript memory leaks from listeners, timers, closures and caches with heap snapshots, then fix the references that keep objects alive.
~2 min readread →
ES Module Live Bindings vs CommonJS: Interview Guide
Why ES module imports see later changes to exported variables, why CommonJS copies values, and how live bindings affect circular imports.
~7 min readread →
Nullish Coalescing (??) vs OR (||) in JavaScript: Defaults Explained
Why || replaces 0, empty strings and false with defaults while ?? only replaces null and undefined, plus ??=, precedence and parameter defaults.
~6 min readread →
Promise.all vs allSettled vs race vs any: JavaScript Interview Guide
How Promise.all, allSettled, race and any settle, what each does on rejection or empty input, and how to pick the right one for real requests.
~7 min readread →
Promise finally() in JavaScript: Cleanup Without Losing Errors
How promise finally() passes results and errors through, when a finally callback overrides the outcome, and how try/finally compares.
~7 min readread →
JavaScript Property Descriptors: writable, enumerable, configurable
How Object.defineProperty and property descriptors control writes, enumeration and deletion, how getters and setters fit in, and their traps.
~6 min readread →
for...in vs Object.keys vs Reflect.ownKeys: Key Order Explained
Which JavaScript APIs list inherited, non-enumerable and symbol keys, and why integer-like keys always come first in object property order.
~6 min readread →
Prototype Pollution in JavaScript: How It Works, How to Prevent It
How __proto__ and constructor.prototype keys in JSON poison every object through unsafe merges, and the defences that close the hole.
~8 min readread →
Remove Duplicates from a JavaScript Array with Set (and Objects)
Why new Set removes duplicate primitives but not duplicate objects, how SameValueZero treats NaN and -0, and how to dedupe objects by key.
~6 min readread →
WeakMap vs Map in JavaScript: Garbage Collection and Leaks
Why WeakMap keys do not keep objects alive, why WeakMaps cannot be iterated, and how to attach caches and private data without leaking memory.
~8 min readread →
Kubernetes Autoscaling and Meaningful Metrics
Kubernetes Autoscaling and Meaningful Metrics. Learn the reasoning, a practical example, common mistakes and an interview exercise.
~2 min readread →
Kubernetes ConfigMaps Versus Secrets
Kubernetes ConfigMaps Versus Secrets. Learn the reasoning, a practical example, common mistakes and an interview exercise.
~2 min readread →
Kubernetes CronJobs and Overlapping Runs
Kubernetes CronJobs and Overlapping Runs. Learn the reasoning, a practical example, common mistakes and an interview exercise.
~2 min readread →
Kubernetes Deployments and Rolling Updates
Kubernetes Deployments and Rolling Updates. Learn the reasoning, a practical example, common mistakes and an interview exercise.
~2 min readread →
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