Processing of 'empty' Values

How Make processes mapped values and how empty values are passed to a service.

The new approach for processing empty values, as described in this document, is applicable only for apps with Apps platform version 2 (apps created after 11/02/2019). Apps with Apps platform version 1 behave according to the old rules due to backward compatibility.

In this approach, almost every input parameter of a module is ignored if there is no value. If the user wants to rewrite (erase) the value of a field in service, the user has to use the erase keyword. Here is an example of how to erase the values for the Query string and Body fields.

The processing of "empty" values is completely managed by Make. So you don't have to implement this in your app. Keep in mind that when an empty value comes to a module, a value still has to be sent to the service.

For example, when a user updates a task and in the module configuration there is a multiple-select with labels that they leave untouched, it is unclear what action should be performed. Does this mean that they want to leave the task labels unchanged or want to remove all the labels?

The new behavior for parameter processing solves this problem.

By default, if the user doesn't select any label, Make will ignore the field. If the user wants to remove all assigned labels from the task, they have to use the erase keyword.

How Make evaluates empty values

Type of empty value	Manifest 1.0	Manifest 2.0 implicit behavior	Manifest 2.0 field with erase pill (map mode)
string	null	undefined	null
string (forced empty string using IML)	""	""	​
number	null	undefined	null
boolean	undefined	undefined	undefined
array	[]	undefined	[]
multiple select	[]	undefined	[]
select (nothing selected)	null	undefined	​
select (selected value is"")	null	undefined	​
select (selected value is null)	invalid value	invalid value	​
select (map mode)	null	undefined	null
collection	not changed (collection of empty values)	Recursively processed corresponding to the rules in this table	Recursively processed corresponding to the rules in this table

Collection example

When using a collection parameter in a module, behavior differs depending on whether fields are left empty or the erase pill is applied:

If the user leaves all fields empty, the request will contain an empty collection.

If the user applies the erase pill to one of the parameters inside collection, Make will send the collection with explicit null values for its fields.

Result: user leaves fields empty

"collection": {}

Result: user applies erase pill

"collection": {
"parameter": null
}

This difference can cause issues in some apps. If the collection values are not modified inside module IML functions and the empty collection is passed directly into the request body or query string, the API may receive {}, which can result in unexpected behavior.

When the erase pill is shown

The erase keyword is shown for the update and universal modules.

The type of module is defined in the metadata of a module. A universal module is a module without a defined module action field.