return produces a bonsai form that will always produce the same value. set and normalize will do nothing to the form provided by this.

return_settable is identical to return, but set and normalize will update the value of the form.

return_error produces a form that always fails validation.

is_valid returns true if value would return Ok.

view_as_vdom produces the vdom representation of the form.

editable defaults to `Yes_always, which should be used when form input can't be disabled. `Currently_yes allows editing, but generates less diff when toggled with `Currently_no. When editable is `Currently_no, the view is wrapped in a fieldset that disables all of the inputs in the form.

Regardless of the value of editable, scheduling the Form.set effect will still change the values in the form.

Known bugs: While setting editable to `Currently_no prevents modification of most browser-builtin input elements, some custom form elements like the drag-and-drop, multiselect, and removing items using the pills in typeahead-multi for don't currently respect this and can be modified anyway. Work is underway to fix these.

set fills the form with the provided value, setting the contents of form-elements if possible

normalize sets the contents of a form to its current value. This only impacts values that have a "normalized" form. For example, a float-producing textbox being normalized might go from displaying "1.000" to "1."

Combines two forms into another one that produces both values from the inputs in tupled form.

Combines a list of forms into another that produces all values from the inputs in list form.

Combines a map of forms into another that produces all values from the inputs in map form.

project is the powerhouse of the library; Using this function, you can change the type produced. Think of it like map.

• parse_exn is a function that converts "forwards". As its name implies, you're free (and encouraged to) throw exceptions when the type conversion would fail.
• unparse goes in the opposite direction. This one must not throw.

Example:

  let _ : int Form.t =
    project
      (a: string Form.t)
      ~parse_exn:Int.of_string
      ~unparse:Int.to_string

The same as project except that the parse function is Or_error returning.

validate can provide additional validation of a value, but unlike project or project', it doesn't change the type of the resulting form

Adds a label to the form.

Same as label, but it lets you use an arbitrary vdom node instead of just a string.

Adds a tooltip to the form.

Same as tooltip, but it lets you use an arbitrary vdom node instead of just a string.

optional takes a 'a t and produces a 'a option t when given a "some detector" and a token "none" value. is_some none must be false.

Example:

  let _ : string option t =
    optional
      (a: string t)
      ~is_some:(Fn.non String.is_empty)
      ~none:""

An alternative "optional form" construction function; optional' gives you the ability to produce the full set of parse options:

• Ok (Some b)
• Ok None
• Error error] while also converting to another type ('a -> 'b option) at the same time.

fallback_to modifies the given form so that Ok default is used as the form's value when it is in an Error state.

Record_builder is the primary way to compose form values using this library.

Unlike the rest of the API which operates on values of type Form.t value values, they operate on Form.t Value.t, and typically return Computation.t.

The functions in this module can be hard to understand Please look at the examples in lib/bonsai/examples/forms/typed.ml