Consider publishing xforms cheat sheet

[mrjones-plip]

I'm writing my first form in medic/cht-core#6727 and think it'd be helpful to new app builders if we documented some top used tricks when building an xlsx

brain dump:

• it can be nice to use google docs to synchronize/archive your xlsx (but cloud is not a backup!) also - see current issue on Improvements pulling files from Google Drive #381
• only show a field when prior select_one or multi_select field is filled out a specific way: set relevent to selected(${attend_clinic}, 'yes')
• only show a field when prior value is not selected: set relevent to not(selected(${attend_clinic}, 'yes'))
• require a date to be in the future (invert > to be in past): constraint to decimal-date-time(.) >= floor(decimal-date-time(today()))
• make patient's age in available in the form:
  • ensure there's a type/name/appearance entry of: db:person/ _id/db-object
  • and another of type/name entry of: hidden/date_of_birth
• Make patient's age avail in years: type/name/calculation of calculate/patient_age_in_years/floor( difference-in-months( ${date_of_birth}, today() ) div 12 )
• Make patient's age avail in months: type/name/calculation of calculate/patient_age_in_months/difference-in-months( ${date_of_birth}, today() )
• Make patient's age avail in days: type/name/calculation of calculate/patient_age_in_days/floor(decimal-date-time(today()) - decimal-date-time(${date_of_birth}) )
• group a set of fields together on a page: appearance to field-list
• how to debug a field's current values: in dev console paste window.debugFormModel(). also see forum post
• tips on how to format a summary page:
  • multiple formatting h1 yellow center
  • use of raw HTML including font awesome
  • which icons you can use - list is here, but how to actually use those icons? use font awesome or include .svg? (answer - it's always use FA in headers - see
• show appropriate formatted age:

  if(${patient_age_in_days} < 31, 
  concat(${patient_age_in_days}, ' days old'),
  if(${patient_age_in_months} < 12, 
  concat(${patient_age_in_months}, ' months old'), 
  concat(${patient_age_in_years}, ' years old')))
  

• get 1 day from today() (or from a user input date with ${input}): format-date-time(date-time(floor(decimal-date-time(today())) + 1), "%Y-%m-%d")
• require a date input to be within next 7 days, set constraint to decimal-date-time(.) >= floor(decimal-date-time(today())) and decimal-date-time(.) <= floor(decimal-date-time(today() + 7))
• show values of form in JS console: window.debugFormModel();
• remind folks of the use of numbers for choices instead ascii text names. this allows you to use both selected() logic as well as < operators
• xlsform website
• Tasks can't be assigned to admin users, "Tasks are available only for users of type “restricted to their place"" - per our docs.
• Offline users won't work on http (non SSL) connections unless you're on localhost. Either user Admin user to be an online user or use ngrok or DIY to enable SSL.
• You want to have a multi-select (select_multiple) with a "none of the above" option that doesn't allow them to select any other options. Set constraint to not(selected(.,'none') and count-selected(.)>1)