export const isUndefined = (value: any) => value === undefined; export const isNull = (value: any) => value === null; export const isBoolean = (value: any) => typeof value === 'boolean'; export const isObject = (value: any) => value === Object(value); export const isArray = (value: any) => Array.isArray(value); export const isDate = (value: any) => value instanceof Date; export const isBlob = (value: any) => value && typeof value.size === 'number' && typeof value.type === 'string' && typeof value.slice === 'function'; export const isFile = (value: any) => isBlob(value) && typeof value.name === 'string' && (typeof value.lastModifiedDate === 'object' || typeof value.lastModified === 'number');