vldt

Object validation made easy.

Defining Fields

To define a field use a string formatted like so:

[<prefix>]<type>[<array_indicator>][<min>][<max>]

Then use this string to create a field:

let field = Field.create(<definition>)

For instance:

let field = Field.create("*int>10")

Prefixes

• * : required. Required fields need to exist and contain a valid other than null or undefined.
• - : hidden. Hidden fields are not projected (see projection).
• ! : unique. Unique fields are not checked by VLDT itself. Use the field's isUnique property when saving data to a database for instance.

Types

• string
• number - accepts both, integers and floats
• int - accepts only integers (i.e. 1.3 would not be accepted)
• float - accepts floats (basically the same as number. When projected values are forced into float format however)
• bool - true, false, and all truthy values (https://developer.mozilla.org/en-US/docs/Glossary/Truthy)
• email

Array Indicator

If a field is supposed to be an array, use the array indicator []. For instance:

'string[]'

Min / Max

To require a minimum / maximum value, use > and <. For instance:

• int>1 - the value needs to be greater than 1.
• int<10 - the value needs to be smaller than 10
• int>1<10 - the value needs to be greater than 1 and smaller than 10

Notes:

• If the type is string, the length of the string is checked.
• If the type is bool, min and max are ignored
• If the type is email, min and max are ignored
• When dealing with an array field, the min and max are used to check the values in the array (not the length of the array. Array length validation will implemented at a later point)

Validation

After creating a field, use its validate(<value>) method:

let result = field.validate(8)

The validation result is an object with two properties:

• isValid - a bool set to true if validation was successful, or set to false if not
• errors - an array containing an object for each validation error. Each of these objects has two properties:
  • message: a string containing a descriptive text of the error encountered
  • reason: a string expressing in one word the reason for the error. The following values are used:
    • required: a value was required but not given
    • type: the value was of the wrong type
    • format: the value was not formatted correctly (e.g. a wrongly formatted e-mail address)

Roadmap

• Array length validation
• Embedded validation