# Conditions Conditions are used to compare values at runtime and add dynamic behavior to your apps. They are configured in the same way as [filters](https://docs.appfarm.io/reference/platform-concepts/filters), but a condition will always return a true or false value. Conditions can be implemented when designing the [UI](https://docs.appfarm.io/reference/apps/ui) (for example to set the **Visibility** property of a component), or building logic in [actions](https://docs.appfarm.io/reference/apps/actions) (for example in an [If action node](https://docs.appfarm.io/library/action-nodes/if)). To build conditions, you should also be familiar with [operators](https://docs.appfarm.io/reference/platform-concepts/operators). ## Condition editor Conditions are constructed using the condition editor. The most basic condition is a single expression made up of a *left operand*, an *operator*, and a *right operand*. In the example below, the left operand is `Ticket.Status`, the operator is `Equals` and the right operand is `New`. The condition is evaluated at runtime and if the status of the ticket is new, the condition will return true.

A condition can also consist of multiple expressions. When you add an additional expression the new expression is compared to the previous expression with an **AND** operator. This means that *both* expressions must equate to true for the condition to return true. You can click the operator to toggle to **OR** and in that case, if *either* expression equates to true the condition will return true. In the example below, the ticket status must be new *and* the description must contain a value (not empty or null) for the condition to return true.

Expressions can be combined within *groups*, and the result of the expressions within a group can be compared. In the example below, the ticket status must be new and the description must contain a value (not empty or null) *or* the ticket must have been created prior to the start of the 2022. If either of these equate to true the condition will return true.

You can add a comment to a condition, and it can be useful to describe how a condition works when it contains many expressions.

### Cardinalities of left and right side operands The right operand may be a single value/object or a list of values/objects, whereas **the left operand may only be a single value or object,** except in the case where the left operand is a property with [Cardinality Many](https://docs.appfarm.io/data-model/object-class-properties#general-properties) (see example 5)**.** Here are some example setups of valid conditions, given the following data sources: * `Person` (Cardinality *One*) * With a property `Department` (with cardinality One) * With a property `Tags` (with cardinality Many) * `Departments` (Cardinality *Many*) * `Tags` (Cardinality Many) #### Example 1

Conditions example with Single cardinality on both sides

In the above example, the left operand is a single value. Since the `EQUALS`-operator is used, the right operand must be a single value. **The right operand is treated as a single value** if the `Departments` Data Source has a single [selected object](https://docs.appfarm.io/reference/objects#object-selection), or if the Departments Data Source has a [context object](https://docs.appfarm.io/reference/objects#object-in-context) (i.e. this condition is placed inside an iterator, such as inside a Foreach action node, looping the Departments Data Source). #### Example 2

This example is similar to example 1, but **the right side is a single property** itself. App Variables is in fact a single cardinality Data Source, and we've added a variable `Selected Department` to it. #### Example 3

In the above example, the left operand is a single value, similar to the previous examples. However, since the operator `EXISTS IN` is used, **the right side is multiple values**. In this case, the right side is a list of the IDs of the selected object in the `Departments` Data Source. #### Example 4

In this example, the left operand is still a single value. However, since the Departments Data Source has cardinality many, the above expression is only valid if the `Departments` Data Source has a single [selected object](https://docs.appfarm.io/reference/objects#object-selection), or if the Departments Data Source has a [context object](https://docs.appfarm.io/reference/objects#object-in-context) (i.e. this condition is placed inside an iterator, such as inside a Foreach action node, looping the Departments Data Source). #### Example 5

In this example, we have a condition towards the multi-reference property `Person.Tags`. You may read more about multi-references [here](https://docs.appfarm.io/how-to/data-modeling/many-to-many-relationships) if you are new to the concept, but in general, it is just a list of IDs (referencing 0 to many `Tags` in this example). In the above condition, we check if the `Person.Tags` list contains some of the selected objects in the `Tags` data source. You may read more about these multi-reference operators (Has All Of, Has Some Of, Has None Of) [here](https://docs.appfarm.io/reference/operators#logical-operators). ## Advanced conditions In some cases, it may not be possible to create the condition you need in the condition editor. If so, you can instead write a function that returns either `true` or `false`. See [Advanced functions](https://docs.appfarm.io/reference/functions#advanced-functions) for examples of advanced conditions.