📄️ Check if a character is a digit
JavaScript version
📄️ Check if a date is a weekday
JavaScript version
📄️ Check if a date is a weekend
JavaScript version
📄️ Check if a date is between two dates
JavaScript version
📄️ Check if a date is today
JavaScript version
📄️ Check if a date occurs in the current year
JavaScript version
📄️ Check if a flat array has duplicate values
JavaScript version
📄️ Check if a given integer is a prime number
JavaScript version
📄️ Check if a number is a power of 2
JavaScript version
📄️ Check if a number is even
JavaScript version
📄️ Check if a number is in a given range
JavaScript version
📄️ Check if a number is negative
JavaScript version
📄️ Check if a number is odd
JavaScript version
📄️ Check if a number is positive
JavaScript version
📄️ Check if a string contains lower case characters
JavaScript version
📄️ Check if a string contains only ASCII characters
JavaScript version
📄️ Check if a string contains only digits
JavaScript version
📄️ Check if a string contains only letters and numbers
JavaScript version
📄️ Check if a string contains only letters
JavaScript version
📄️ Check if a string contains upper case characters
JavaScript version
📄️ Check if a string contains whitespace
JavaScript version
📄️ Check if a string is a hexadecimal color
JavaScript version
📄️ Check if a string is a hexadecimal number
JavaScript version
📄️ Check if a string is a MongoDB ObjectId
JavaScript version
📄️ Check if a string is an octal number
JavaScript version
📄️ Check if a string is lower case
JavaScript version
📄️ Check if a string is upper case
JavaScript version
📄️ Check if a value is a business identifier code
JavaScript version
📄️ Check if a value is a number
JavaScript version
📄️ Check if a value is a plain object
JavaScript version
📄️ Check if a value is a regular expression
JavaScript version
📄️ Check if a value is a string
JavaScript version
📄️ Check if a value is an object
JavaScript version
📄️ Check if a value is base32 encoded
JavaScript version
📄️ Check if a value is base58 encoded
JavaScript version
📄️ Check if a value is base64 encoded
JavaScript version
📄️ Check if a value is nil
JavaScript version
📄️ Check if a year is leap year
JavaScript version
📄️ Check if all array elements are equal to a given value
JavaScript version
📄️ Check if all items in an array are equal
JavaScript version
📄️ Check if an array contains a value matching some criterias
JavaScript version
📄️ Check if an array is not empty
JavaScript version
📄️ Check if an array is subset of other array
JavaScript version
📄️ Check if an object is a Promise
JavaScript version
📄️ Check if an object is an array
JavaScript version
📄️ Check if an object is empty
JavaScript version
📄️ Validate a Gregorian date
JavaScript version