Enable three unicorn rules — one correctness, two performance — and fix every
existing violation repo-wide so the rules pass as errors.
prefer-number-properties (76 sites)
- parseInt/parseFloat/NaN -> Number.* : safe aliases (autofixed).
- isNaN -> Number.isNaN (12 sites, hand-converted): global isNaN coerces its
argument, Number.isNaN does not. Verified every call site already passes a
number (Number.parseInt results, number-typed fields, Date.getTime()), so the
conversion is behavior-preserving today and guards against a future non-numeric
argument silently coercing.
prefer-array-find (26 sites)
- .filter(pred)[0] -> .find(pred); .filter(pred).at(-1) / .pop() -> .findLast(pred).
Drops the intermediate array and short-circuits.
prefer-array-index-of (5 sites)
- .findIndex(x => x === v) -> .indexOf(v).
Verified: typecheck (node/cli/web) clean, 53 affected suites pass (1679 tests),
oxlint clean repo-wide. mobile/ uses findLast safely (already ships ES2023
.toReversed()); config scripts and e2e helpers run on Node 24.
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