JavaScript Math.max RangeError on Large Arrays: Scan the Values
Reproduce the Math.max RangeError with spread and apply on a large array, then verify a scan that preserves NaN and signed zero behavior.
352 words 2 minutes
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URLSearchParams Turns Plus Signs into Spaces: Preserve Literal +
Trace where URLSearchParams loses a literal plus sign. Compare raw queries, set(), and pre-encoded inputs with round-trip checks for +, spaces, and %2B.
419 words 2 minutes
JavaScript Promise finally Masks the Original Error: Keep Both Failures
See why Promise.finally can hide a rejected operation when cleanup fails, then run six Node.js checks for a wrapper that preserves both rejection reasons.
542 words 3 minutes
JavaScript isNaN Accepts Empty Strings: Validate Required Numbers
See why isNaN accepts blank strings, then test a form parser that keeps zero and rejects blank or non-finite amounts before they reach a JSON payload.
520 words 3 minutes
JavaScript toSorted Turns Array Holes into undefined: Keep Empty Slots
See how toSorted and spread change sparse array holes into undefined, then verify that slice().sort() preserves the hole count and leaves the source intact.
405 words 2 minutes
JavaScript Promise.race Timeout Does Not Cancel Work: Use an AbortSignal
Prove that a Promise.race timeout leaves work running, then compare result selection with abortable Node.js timers and explicit cleanup ownership.
645 words 3 minutes
JavaScript Object.keys Reorders Numeric Keys: Preserve Insertion Order
Trace numeric key ordering, leading zeros, and the array-index limit with executable checks. Preserve insertion order with Map or JSON entry arrays.
649 words 3 minutes
JavaScript every Returns true for Empty Arrays: Validate Required Lists
Fix required-list validation with a runnable every() matrix covering empty arrays, sparse slots, and inherited entries, plus an explicit own-entry guard.
796 words 4 minutes