There seem to be no way to flag a text field as optional (not required)

[Andy]

Subject...

[Maxime Mangel]

I forgot to expose the function for it, it is now available.

See the doc comment, to know more about how to use it:

Fable.Form/packages/Fable.Form.Simple/Form.fsi

Lines 186 to 217 in 4cb633c

     /// <summary> 
     /// Make a form be <b>optional</b> 
     /// 
     /// If the form has values set, it will return <c>Some 'Value</c>. 
     /// 
     /// Otherwise, it returns <c>None</c>. 
     /// </summary> 
     /// <param name="form">Form to make optional</param> 
     /// <example> 
     /// <code lang="fsharp"> 
     /// let emailField = 
     ///     Form.emailField 
     ///         { 
     ///             // ... 
     ///         } 
     /// 
     /// let ageField = 
     ///     Form.numberField 
     ///         { 
     ///             // ... 
     ///         } 
     /// 
     /// let onSubmit = 
     ///     fun email ageOpt -> 
     ///         LogIn (email, ageOpt) 
     /// 
     /// Form.succeed onSubmit 
     ///     |> Form.append emailField 
     ///     |> Form.append (Form.optional ageField) 
     /// </code> 
     /// </example> 
     /// <returns>An optional form</returns> 

Also, making a form optional returns 'T option