normalizeInteger

Normalizes a value into an integer or returns null. This helper accepts finite native integers and string representations of integers. It trims string input before parsing and rejects floats, NaN, Infinity, and malformed numeric values.

It never throws and never mutates input. Use this when you need a predictable integer before validation or further processing.

Signature

function normalizeInteger(value: unknown): number | null

Parameters

Name	Data type	Description
value	unknown	The value to normalize into an integer.

Returns

One of:

• A finite integer.
• null: If the value cannot be interpreted as an integer.

Behavior

• Accepts finite native integers.
• Scientific notation is allowed when it normalizes to an integer.
• Accepts integer strings (trimmed before parsing).
• Rejects:
• Floats.
• NaN.
• Infinity and -Infinity.
• Empty strings.
• Whitespace‑only strings.
• Malformed numeric strings.
• All non‑string, non‑number values.
• No mutation, no exceptions, no hidden coercion.

Examples

normalizeInteger(42)            // 42
normalizeInteger("42")          // 42
normalizeInteger("  -10  ")     // -10

normalizeInteger(3.14)          // null
normalizeInteger("3.14")        // null
normalizeInteger("")            // null
normalizeInteger("abc")         // null
normalizeInteger(Infinity)      // null

Notes

• Use normalizeSafeInteger if you need to enforce the safe integer range.
• Use validateInteger if you need a Result<T> instead of null.