Datasets: Add select and multi-select fields

An issue that keeps coming up with Projects is that owners want to be able to provide a list of options for contributors to pick from. At the moment the workaround is to use a plain text box or a series of Yes/No fields.

A plain text box has the limitation that contributors will inevitably enter values in different formats (different capitalisations, hyphenations, spellings, CSV, separated by line breaks, etc) and different orderings. This makes it difficult to filter by values in this field.

The other option is to use a series of Yes/No field types, but this can require breaking up the project into multiple projects so that the extraction form doesn’t get too long.

Adding a select and multi-select field type would be a relatively easy win to solve these issues and make Projects even more useful.

Frontend

We might want to refer to this as a “drop down”, since that seems to be the terminology most often used when users have asked about this.

Adding user-enterable values adds additional complexity not only in the backend but in the form builder. An idea here could be to contain any “configuration” for the field within a modal.

This would keep the main form builder consistent in its 3 main columns (title, field type, remove button), and then reveal specific field configuration only when necessary.

We’d likely want to validate that at least two options are present.

Backend

For the current fields we only store the fields type and user entered title. For select fields we’ll also need to store the option values.

Initially we’ll limit the select field to a flat list of options – i.e. no optgroups. If its easy we could add an "allow blank" option to the "configuration", but not essential.

Submissions & Dataset Output

For single-select fields, we’ll just render the column with the value as normal.

Multi-select will mean we'll now have to deal with a multi-value field.

We’ll handle multi-select by storing the the selected values as a CSV string and render it within the single column.

other,headings,cars,boolean
foo,bar,"volvo, ford, mercedes",Yes

We’ll need to think about where this could break, and limit the format of the options accordingly.