Collection chunking via @timvermeulen

Collection+Chunking.swift

extension Collection {
    func chunk(size: Int) -> ChunkedCollection<Self> {
        ChunkedCollection(self, size: size)
    }
}

struct ChunkedCollection<Base: Collection>: Collection {

    private let base: Base
    
    private let chunkSize: Int
    
    fileprivate init(_ base: Base, size: Int) {
        self.base = base
        chunkSize = size
    }

    typealias Index = Base.Index
    
    var startIndex: Index {
        base.startIndex
    }
    
    var endIndex: Index {
        base.endIndex
    }
    
    func index(after index: Index) -> Index {
        base.index(index, offsetBy: chunkSize, limitedBy: base.endIndex) ?? base.endIndex
    }
    
    subscript(index: Index) -> Base.SubSequence {
        base[index..<self.index(after: index)]
    }
}

extension ChunkedCollection: Equatable where Base: Equatable {}

extension ChunkedCollection: Hashable where Base: Hashable {}