You Selected Rows 3, 8, 12, 15 and 20. JavaScript Checked 3, 1 and 8.
Why ['1', '7', '11'].map(parseInt) returns [1, NaN, 3]: map passes the index as parseInt's radix. Plus the Number('') trap hiding in the obvious fix.
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Why ['1', '7', '11'].map(parseInt) returns [1, NaN, 3]: map passes the index as parseInt's radix. Plus the Number('') trap hiding in the obvious fix.
Why JavaScript's sort() compares numbers as strings, why a 'lazy' comparator works in Safari but breaks in Chrome, and the one-line fix.
Cross-Origin Resource Sharing in plain language: what blocks your request, what preflight means, and how to fix the errors you'll see in every frontend job.
Two patterns for taming fast events: debounce waits for silence, throttle limits how often. With examples, code, and interview answers.
`||` treats 0 and '' as missing. `??` only treats null/undefined as missing. Know the difference before it bites you in an interview or in prod.
Why your effect reads old state, fires twice, or loops forever — and the simple rules to fix it (interview-ready).