validate.presence

validate.presence returns a given value if the value is present or an error if the value is not present.

Function category: Validate​

Syntax

validate.presence(arg1, arg2)

Examples

Let's say we receive the following data structure.

{
  "driver_ids":
  {
    "first": 999,
    "second": null
  }
}

Example 1: Determine if a value exists

If we want to perform an operation but aren't sure whether the value exists, we can check if the first value exists using the following function.

# Confirm if a value exists. 
validate.presence(driver_ids.first, 
                  "This error message won't be executed")
​
# Returns 999
#
# This value indicates the value exists

Example 2: Determine if another value exists

We can check the second value exists using the following function.

# Conform
validate.presence(driver_ids.second, 
                  "Value was null!")
​
# Returns "Value was null!"
#
# This value does not exist