> For the complete documentation index, see [llms.txt](https://ios-course.cornellappdev.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ios-course.cornellappdev.com/resources/textbook/persistence-+-snapkit/snapkit.md).

# SnapKit

Tired of having to type the extremely long code for setting up auto-layout with NSLayout? SnapKit is here to make our lives easier! SnapKit is a wrapper library that makes setting constraints with auto-layout very simple.

### Installation

You can use either Swift Package Manager or CocoaPods to install SnapKit. If using CocoaPods, simply write `pod SnapKit` in our Podfile then use `pod install`.

### Using SnapKit

The best way to understand how to use SnapKit is to compare it with the code that we have written so far.

```swift
// NSLayout
NSLayoutConstraint.activate([
    child.leadingAnchor.constraint(equalTo: parent.leadingAnchor),
    child.topAnchor.constraint(equalTo: parent.topAnchor),
    child.trailingAnchor.constraint(equalTo: parent.trailingAnchor),
    child.bottomAnchor.constraint(equalTo: parent.bottomAnchor)
])

// SnapKit (note that we do not need commas)
child.snp.makeConstraints { make in
    make.leading.equalToSuperview()
    make.top.equalToSuperview()
    make.trailing.equalToSuperview()
    make.bottom.equalToSuperview()
}

// Or we can do the following
child.snp.makeConstraints { make in
    make.leading.top.trailing.bottom.equalToSuperview()
}

// Or even the following
child.snp.makeConstraints { make in
    make.edges.equalToSuperview()
}
```

```swift
// NSLayout with insets, height/width, and relative to other subviews
NSLayoutConstraint.activate([
    childTwo.leadingAnchor.constraint(equalTo: childOne.trailingAnchor, padding: 16),
    childTwo.trailingAnchor.constraint(equalTo: parent.trailingAnchor, padding: -16),
    childTwo.centerYAnchor.constraint(equalTo: childOne.centerYAnchor),
    childTwo.heightAnchor.constraing(equalToConstant: 96)
])

// SnapKit Version
childTwo.snp.makeConstraints { make in
    make.leading.equalTo(childOne.snp.trailing).offset(16)
    make.trailing.equalToSuperview().offset(-16) // or .inset(16)
    make.centerY.equalToSuperview()
    make.height.equalTo(96)
}
```

```swift
// Using SafeAreaLayoutGuide
make.top.equalTo(view.safeAreaLayoutGuide.snp.top)
make.bottom.equalTo(view.safeAreaLayoutGuide.snp.bottom)
```

SnapKit offers a lot more than just these basic constraints so feel free to Google! We also do not have to set `translatesAutoresizingMaskIntoConstraints` to `false` when using SnapKit!