Initial Data

Sometimes you want to provide sane defaults for fields in a form. To do this you can use the :initial entry in the defform option map. For example:

(defform sample-form {:initial {:email "user@example.com"}}
  :email []
  :message [])

When creating a fresh form, this initial data will populate the :data map in the result instead of the default empty string:

(sample-form)
; =>
{:fresh true
 :results nil
 :data {:email "user@example.com"
        :message ""}
 ...}

When you run some data through the form, the initial data is ignored completely:

(sample-form {:email "foo@bar.com"
              :message "hi"})
; =>
{:fresh false
 :results {:email "foo@bar.com"
           :message "hi"}
 :data    {:email "foo@bar.com"
           :message "hi"}
 ...}

This means when you're rendering a form field to HTML you can simply pull the field's entry from the :data map and fill the field with its contents. It doesn't matter whether it happened to be a fresh form or a form that had some errors.

Note that initial data should always be specified as a string, since the :data map will always contain strings once you've run data through it.

Move on to the form arguments guide next.