This a utility/developer-only module for converting fields from one type to another. E.g., for changing plain text (textarea) fields to filtered text (WYSIWYG), or short text fields to long text. Existing field data is preserved as long as the new field type schema has columns with the same names as the old schema (e.g., "value").
This module works to provide JSON output for all fields information for any entity type via a menu_callback so it can be integrated into any other application such as the Ionic framework.