Represents a form field value.

A blank value.

Use this to initialize the values of your empty fields:

values : SignupValues
values =
    { email = Value.blank
    , password = Value.blank
    , rememberMe = Value.blank
    }

Build an already filled value.

Use this when you are using forms to edit existing values:

values : Profile -> ProfileValues
values profile =
    { firstName = Value.filled profile.firstName
    , lastName = Value.filled profile.lastName
    }

Obtain the data inside a Value.

If the value is blank, it returns Nothing, else it returns Just the value.

Note: You should only be using this in meta forms or custom view code.

Update a value with new data.

Note: You should not need to care about this unless you are creating your own custom fields.

Transform a value.

For instance, this can be useful if you want to use a Form.numberField with a Value Int instead of Value Float:

numberOfApples : Form { r | number : Value Int } Int
numberOfApples =
    Form.numberField
        { parser = round >> Ok
        , value = .number >> Value.map toFloat
        , update =
            \value values ->
                { values | number = Value.map round value }
        , attributes =
            { label = "How many apples do you have?"
            , placeholder = "Type a number"
            , step = 1
            , min = Just 0
            , max = Nothing
            }
        }

Select the newest value out of two sets of values.

This is necessary to fix an issue with autocompletion. When a form is autocompleted, many events can get triggered before the view can be rerendered, causing the first autocompleted values to be lost.

newest allows to fix this:

update : Msg -> Model -> Model
update msg values =
    FormChanged newForm ->
        { form |
            values =
                { email = Value.newest .email form.values newForm.values
                , password = Value.newest .password form.values newForm.values
                }
        }

Note: This issue seems fixed in Elm 0.19, thus this function will be removed soon.