Explain JavaScript Numeric Edge Cases

# Explain JavaScript Numeric Edge Cases Explain how JavaScript distinguishes numeric values, integers, `NaN`, and infinities. Compare `typeof`, `Number.isInteger`, `Number.isNaN`, `Number.isFinite`, numeric conversion, and partial string parsing. Correct the assumption that a standard `Number.isNumber` method exists. ### Constraints & Assumptions - Discuss primitive numbers; mention `BigInt` only where it changes the boundary. - Include coercion and safe-integer precision pitfalls. ### Clarifying Questions to Ask - Is the goal validation of already typed values or parsing user input? - Should numeric strings be accepted, and must the entire string be valid? ```hint Separate type, finiteness, and integrality No single check answers all three questions, and parsing adds a separate coercion policy. ``` ### What a Strong Answer Covers - Accurate behavior for `NaN`, positive and negative infinity, and `-0`. - Non-coercing `Number` predicates versus coercing global functions. - Whole-string conversion versus prefix parsing. - `Number.isSafeInteger` and precision beyond the safe range. ### Follow-up Questions - How would you validate a form field that must be a finite safe integer? - Why can a mathematically non-integer decimal be represented as an integer after rounding?