# If / Else If / Else

The `if` flow evaluates the given expression and executes the body if the expression resulted in `true`. Otherwise, the body is ignored. It can be chained with `else if` and `else`, stopping the execution after the first expression resulting in `true`. 

`If` must always start the condition chain and can be optionally followed by `else if` and `else`. `Else` has to always be the last, and can only be used in the chain.

## Syntax

Basic syntax of `if` tag is as follows:

```swift
{[ if [statement] ]}
   Content that gets executed when statement evaluates to true
{[/]}
```

When additional conditions are needed, use `else if` and / or `else` to chain them:

```swift
{[ if [statement] ]}
   Content that gets executed when first statement evaluates to true
{[ elseif [statement] ]}
   Content that gets executed when first statement evaluates to false and second to true
{[ else ]}
   Content that gets executed when everything above evaluates to false (fallback)
{[/]}
```

Note that `else` doesn't have `statement` as it serves as a fallback when everything else fails.

## Evaluating the statement

> This section is a work in progress. If definition is not yet complete

`if` or `else if` evaluates to true when one of the following conditions is true:

* `statement` resulting type is `Boolean` and  `== true`
* `statement` resulting type is `Int` and `>= 1`
* `statement` resulting type is `String` and the string is not empty

## Example use case

`If` can be used to render structurally different data based on the input values. In this example, a different user menu gets rendered based on whether the user is admin, team member, or a visitor.

**Data**

```javascript
{
    "user": {
        "name": "Jiri",
        "type": "member"
    }
}
```

**Blueprint**

```markup
<ul>
    {[ if user.type.equals("admin") ]}
    <li>Manage Database</li>
    <li>Manage Users</li>
    <li>Manage Team</li>
    {[ elseif self.user.type.equals("member") ]}
    <li>Manage Team</li>
    {[ else ]}
    <li>Request Membership</li>
    {[/]}
    <li>Logout</li>
</ul>
```

**Result**

```markup
<ul>
    <li>Manage Team</li>
    <li>Logout</li>
</ul>
```

Finally, if we change `user.type` to `admin`, the output will look like the following:

```markup
<ul>
    <li>Manage Database</li>
    <li>Manage Users</li>
    <li>Manage Team</li>
    <li>Logout</li>
</ul>
```