jaredramirez / elm-field / Field

This library provides a datatype to model and validate input field data.

For an example, take a look at the README

Base


type Field value error

The field type, it represents all the possible state that a field can be in. It has take parameters of an error type and a value type.

Unless you're trying to model some unique data you probably won't be using this type, but one with the value and error arguements already applied. Take a look at the Field.String, Field.Int and Field.Float modules to see some common types already appplied and for examples to modeling your own data.


type alias Metadata =
{ active : Basics.Bool
, touched : Basics.Bool
, disabled : Basics.Bool 
}

A type to reperesent various bits of data about any individiual field. You can get this record from a field with extractMetadata, and set this record with resetMetadata

Viewing fields


type alias ViewConfig value error msg =
{ valid : Metadata -> value -> Html msg
, invalid : Metadata -> value -> error -> Html msg 
}

A mapping from different field statuses to Html

view : ViewConfig value error msg -> Field value error -> Html msg

Takes a ViewConfig and a field and uses the different possible Html based on the field's status

Interacting with fields

init : value -> Field value error

Create a new field with the given value that is in a valid status

resetValue : Field value error -> value -> Field value error

Reset a field with a new value, and set it to the valid status

extractValue : Field value error -> value

Extract the metadata from a field, regardless of the field's status

resetMetadata : Field value error -> Metadata -> Field value error

Reset a field with new metadata

extractMetadata : Field value error -> Metadata

Extract the value from a field, regardless of the field's status

withDefault : value -> Field value error -> value

Return the value of a field if it is in a valid status, otherwise get the default value provided

toMaybe : Field value error -> Maybe value

Convert a field to a Maybe. This discards the error.

toResult : Field value error -> Result error value

Convert a field to a Result

isValid : Field value error -> Basics.Bool

Returns true if the field in currently in a valid state, false otherwise

isInvalid : Field value error -> Basics.Bool

Returns true if the field in currently in a invalid state, false otherwise

Validation


type alias ValidationFunc value error =
Field value error -> Field value error

Type alias that takes a field, and returns a field

test : (value -> Basics.Bool) -> error -> ValidationFunc value error

Alias to createValidator. Deprecated.

createValidator : (value -> Basics.Bool) -> error -> Field value error -> Field value error

Create a validator by testing a field against the provided function. If the field passes then return the field the exact same, otherwise return a field marked as invalid with the provided error. If the field is already invalid, then this function just returns the field as it got it. This is to keep the exisitng error, so you can chain together validation functions easily.

Look to the Field.String, Field.Int and Field.Float modules in this package. for pre-created validation functions.