# Condition

The Condition step determines the next step in the action by evaluating a JavaScript expression. Return `true` to execute the <mark style="color:green;">if</mark> step, or `false` to execute the <mark style="color:red;">else</mark> step.

```javascript
return {{data.length}}  > 0;
```

## **Variables**

### **Built-in variables**

The following built-in variables are available for the Condition step:

```javascript
// result of the previous step
return {{data}};

// error response of the previous step
return {{error}};

// incoming action params, passed in by components,
// the Execution/Loop action steps or when calling the action from the code
return {{params}};

// the response of the request, if the Code step follows an HTTP API step
return {{res}};
```

While `{{data}}` and `{{error}}` are specific to a particular step, `{{params}}` is available in all steps.

### **Using variables**

```javascript
// use `{{data.<key>}}` to access a specific key
return {{data.name}};

// to access the first element of the array
return {{data[0]}};

// to access the `name` key of the first element
return {{data[0].name}};
```

### **Optional chaining**

If, at some point, the variable's value is `null` or `undefined`, an optional chaining operator `?.` can be used to access a specific key.

For example:

```javascript
// if `data` is `null` or `undefined`, `name` will not produce an error
return {{data?.name}};
// if `data` is `null` or `undefined`, `name` will not produce an error
return {{data?.[0]?.name}};
```

## Use case examples&#x20;

Execute the `true` step if the `data` array has some items:

```javascript
return {{data.length}}  > 0;
```

Execute the `true` step if the component's value is set:

```javascript
return !!{{ui.input.value}};
```

Check user role:

```javascript
return {{user.role}} === 'admin';
```

Check multiple user roles:

```javascript
return ['admin', 'manager'].includes({{user.role}});
```

Check that at least one user role is present:

```javascript
return ['admin', 'manager'].some(role => {{user.roles}}.includes(role));
```


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