Javascript Developer Interview Questions

1,200 javascript developer interview questions shared by candidates

The interviewer asked questions mainly related to JavaScript concepts, React fundamentals, HTML/CSS basics, and basic problem-solving. Some questions were conceptual, while others required explaining real-world usage and examples.
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Javascript Developer

Interviewed at TO THE NEW

3.7
Dec 20, 2025

The interviewer asked questions mainly related to JavaScript concepts, React fundamentals, HTML/CSS basics, and basic problem-solving. Some questions were conceptual, while others required explaining real-world usage and examples.

The hardest interview was behavioral. Most interviewees fail at that stage so prepare well. The questions are all standard and expected. JS interview was about a basic lodash like functionality implementation. React interview was about implementing a search functionality but the crux was about performance algo optimization via data appropriate structures. Both interviewers asked about time space complexity and both requested second attempt at improving your basic solution if not in code since little time will be left but in words. The deep dive was about picking some project from the past that you know good and diving deep into technical and architectural aspects testing your general understanding of how things work together.
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Senior Software Engineer (JavaScript)

Interviewed at Elastic

3.9
Feb 8, 2024

The hardest interview was behavioral. Most interviewees fail at that stage so prepare well. The questions are all standard and expected. JS interview was about a basic lodash like functionality implementation. React interview was about implementing a search functionality but the crux was about performance algo optimization via data appropriate structures. Both interviewers asked about time space complexity and both requested second attempt at improving your basic solution if not in code since little time will be left but in words. The deep dive was about picking some project from the past that you know good and diving deep into technical and architectural aspects testing your general understanding of how things work together.

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Glassdoor has 1,200 interview questions and reports from Javascript developer interviews. Prepare for your interview. Get hired. Love your job.