React Native Interview Handbook — Part 6 of 10: Output-Based JavaScript Practice

This is Part 6 of 10 , a bonus practice article containing 191 output-based JavaScript interview questions . It includes 111 questions drawn from the React Native Interview Handbook plus 80 additional questions on the JavaScript behavior interviewers commonly test in React Native rounds: hoisting, scope, closures, arrays, objects, functions, coercion, conditions, Promises, and the event loop. Complete series This Dev.to series has five core handbook articles plus five focused practice extras. Open the series page to move through the complete reading order: Part 1: JavaScript — core handbook, questions 1–120 Part 2: React — core handbook, questions 121–220 Part 3: React Native — core handbook, questions 221–420 Part 4: Performance & Architecture — core handbook, questions 421–560 Part 5: Senior & System Design — core handbook, questions 561–719 Part 6: Output-Based JavaScript Practice — bonus practice article Part 7: Coding Interview Practice — bonus practice article Part 8: Code Output Challenges — bonus practice article Part 9: Current React Native Interview Questions — new high-frequency practice article Part 10: Project & Production Interviews — senior project ownership and real-production practice How to use this guide Before opening an answer, state the exact output first. Then explain the rule that causes it: evaluation order, scope, coercion, reference identity, prototype lookup, or microtask scheduling. Run the snippet only after committing to an answer. Topics covered Hoisting, Temporal Dead Zone, var , let , const , and function declarations Scope, closures, this , arrow functions, call , apply , and bind Arrays, sparse arrays, map , reduce , sort , slice , splice , and mutation Objects, references, shallow copies, prototypes, getters, and property lookup Conditions, truthiness, equality, nullish coalescing, and type coercion Promises, async / await , microtasks, timers, and error recovery React and React Native rendering behavior, state updates, effects,