Assist_Design/packages/domain/toolkit/typing/guards.ts

/**
 * Toolkit - Type Guards
 *
 * Type guard utilities for runtime type checking.
 */

/**
 * Check if value is a non-null object
 */
export function isObject(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

/**
 * Check if value is a non-empty array
 */
export function isNonEmptyArray<T>(value: unknown): value is [T, ...T[]] {
  return Array.isArray(value) && value.length > 0;
}

/**
 * Check if value is a string
 */
export function isString(value: unknown): value is string {
  return typeof value === "string";
}

/**
 * Check if value is a number
 */
export function isNumber(value: unknown): value is number {
  return typeof value === "number" && !isNaN(value);
}

/**
 * Check if value is a boolean
 */
export function isBoolean(value: unknown): value is boolean {
  return typeof value === "boolean";
}

/**
 * Check if value is null or undefined
 */
export function isNullish(value: unknown): value is null | undefined {
  return value === null || value === undefined;
}

/**
 * Check if value is defined (not null or undefined)
 */
export function isDefined<T>(value: T | null | undefined): value is T {
  return value !== null && value !== undefined;
}

/**
 * Filter out null/undefined values from array
 */
export function filterDefined<T>(arr: (T | null | undefined)[]): T[] {
  return arr.filter(isDefined);
}