In the creation of the Data Layer Manager, SDI Tooklit, and AA Product String extensions, I have created or worked with various new data elements that are expected to have return types other than simple string values.
One example is the Malformed URL Error data element of the SDI Toolkit which can return an Array of Strings.
Another is the Data Layer Manager's Contextual Data Element which can return a JSON object, an Array of JSON objects, boolean, number, or string depending on how it is configured.
As more Launch extensions are created, it is inevitable that new Data Element Types will be introduced with a strong possibility of different expected return types.
As this happens, it would be incredibly valuable for extensions using data element selectors to be able to filter the data elements returned to include only those that meet the needs of the extension.
1) In the configuration of a Data Element instance, allow the author to specify the expected return type by selecting from a drop-down ["string", "number", "array", "object", "regexp", "function"].
2) From an Extension View when calling the data element selector, window.extensionBridge.openDataElementSelector([options: Object]), allow the expected return type(s) to be specified in the options object. The effect of this would be a filtered list of data elements.