/**
 * Checks if the provided value is a valid finite number, excluding NaN (Not-a-Number)
 * and infinite values (Infinity and -Infinity).
 *
 * This function performs a type check to ensure the value is of type `number` and
 * additionally verifies that it is finite and not NaN, which are special numeric values
 * representing invalid or infinite numbers.
 *
 * It serves as a type guard, narrowing the type of the input value to `number` if the check passes.
 * This is useful in TypeScript for ensuring type safety when dealing with potentially
 * untrusted or dynamically typed inputs, such as user inputs, API responses, or parsed data.
 *
 * @param value - The value to check. Can be of any type, but the function will only return true
 *                for actual finite numbers.
 * @returns `true` if the value is a finite number and not NaN; otherwise, `false`.
 *          When `true`, TypeScript will narrow the type of `value` to `number`.
 *
 * @example
 * ```typescript
 * console.log(isNumber(42));        // true
 * console.log(isNumber(3.14));      // true
 * console.log(isNumber(NaN));       // false
 * console.log(isNumber(Infinity));  // false
 * console.log(isNumber(-Infinity)); // false
 * console.log(isNumber('42'));      // false
 * console.log(isNumber(null));      // false
 * console.log(isNumber(undefined)); // false
 * ```
 *
 * @note This function does not consider numeric strings (e.g., "42") as numbers.
 *       For parsing strings to numbers, consider using `parseFloat` or `parseInt`
 *       in combination with this check.
 * @note This function rejects infinite values (Infinity/-Infinity) as they typically
 *       represent error conditions or overflow in validation contexts.
 */
export declare function isNumber(value: unknown): value is number;