scottrhoyt/swifttilejson

Usage

let tileJSON = try JSONDecoder().decode(TileJSON.self, from: tileJSONData)

Structured `Bounds` and `Center`

The TileJSON 3.0 spec uses arrays with implicit structure for the bounds and center fields. To make working with this data eaiser, SwiftTileJSON maps these to the TileJSON.Bounds and TileJSON.Center structs.

let tileJSON = try JSONDecoder().decode(TileJSON.self, from: tileJSONData)
print(tileJSON.bounds?.maxLongitude)
print(tileJSON.center?.zoom)

Custom Fields Handling

The TileJSON 3.0 spec requires that all implementations provide access to custom key/value pairs that are included in the object, but not covered in the spec. The TileJSON object provides the base fields of the spec in a nested struct that preserves Equatable and Hashable conformance. Any additional fields are captured in the extendedFields property. TileJSON.Base can be used directly to encode/decode when extendedFields are not needed.

To improve the ergonomics of using TileJSONs and TileJSON.Bases together, both conform to the TileJSONFields protocol.

let tileJSON = try JSONDecoder().decode(TileJSON.self, from: tileJSONData)
let baseFields = tileJSON.base
let extendedFields = tileJSON.extendedFields

// You can utilize all base fields from either struct
print(tileJSON.name)
print(tileJSON.base.description)

// The underlying `TileJSON.Base` struct maintains `Equatable` and `Hashable` conformance.
let tileJSONBase = try JSONDecoder().decode(TileJSON.Base.self, from: tileJSONData)
assert(tileJSONBase == tileJSON.base)

Default Values

The TileJSON 3.0 spec states that implementations MAY use default values for certain fields where they are not provided or invalid. In some use cases, it is useful to have access to the default values and to know when the original values were either not provided or invalid. To implement this, the TileJSON object contains nil values where fields were not provided or invalid, and the TileJSONFields protocol defines access to properties that are overriden with their default values in the case of a nil decoded value. These fields are named with the pattern effectiveFieldName.

let tileJSON = try JSONDecoder().decode(TileJSON.self, from: tileJSONData)
let maxZoomOrDefault = tileJSON.effectiveMaxZoom

Package Metadata

Repository: scottrhoyt/swifttilejson

Default branch: main

README: README.md