JadenGeller

struct OnChangeTask<T: Equatable>: ViewModifier {
    let value: T
    let action: () async -> Void
    @State private var updateCount = 0
    
    func body(content: Content) -> some View {
        content
            .onChange(of: value) {
                updateCount += 1
            }

JadenGeller

/// A view that displays a collection of items in a scrollable list that can "zoom" to focus on a single selected item.
///
/// `ZoomNavigator` provides a navigation pattern similar to the iOS lock screen wallpaper picker,
/// where items can be viewed together in a scrollable list or individually in full screen.
/// The same view instance is maintained during transitions, preserving state and identity.
///
/// When no item is selected (`selection` is `nil`), all items are displayed in a scrollable list.
/// When an item is selected, the view filters to show only that item, expanded to fill the available space.
struct ZoomNavigator<Data: RandomAccessCollection, ID: Hashable, Content: View, Background: View, Modifier: ViewModifier>: View {
    var data: Data

JadenGeller

The Service Linker Pattern

Build compositional service architectures where dependencies wire themselves, boundaries cost nothing, and testing happens at exactly the right level.

// Two services that both need users - automatically shared!
struct AppBundle: LinkOrder & LinkNotification {
    let db = PostgreSQL()
    let email = SendGrid()
}

JadenGeller

import SwiftUI

struct AttributedStringBuilder {
    @Stack var attributes: RichTextAttributes = .init()
    var string: AttributedString = ""
    
    mutating func text(_ span: String) {
        string += AttributedString(span, attributes: .init(attributes))
    }
    

JadenGeller

@propertyWrapper
struct Stack<Value> {
    private var history: [Value]

    init(wrappedValue initialValue: Value) {
        self.history = [initialValue]
    }

    var wrappedValue: Value {
        get { history[history.endIndex - 1] }

JadenGeller

Markdown Extensions

Component Directives

• Component Directive: A code block that defines a custom component.
• Info String: Starts with a $COMPONENT-NAME, which is @ followed by an $IDENTIFIER (e.g., @component-name).
• Front Matter: Enclosed within --- delimiters, specifies component attributes.
• Nesting: Use more backticks for the parent block than the child, respecting CommonMark.
• Content: Valid markdown, which may nest component directives.

Examples

JadenGeller

from itertools import zip_longest, chain
from dataclasses import dataclass, field

@dataclass
class Tree:
    value: any
    children: list = field(default_factory=list)
    
    def levels(self):
        yield [self]

JadenGeller

struct RangeSliceCollection<Base: Collection, Ranges: Collection>: Collection where Ranges.Element == Range<Base.Index> {
    var base: Base
    var ranges: Ranges
    
    var startIndex: Ranges.Index { ranges.startIndex }
    var endIndex: Ranges.Index { ranges.endIndex }
    
    func index(after i: Ranges.Index) -> Ranges.Index {
        ranges.index(after: i)
    }

JadenGeller

extension Task where Success == Never, Failure == Never {
    static let perpetual = Task {
        await withCheckedContinuation { (_: CheckedContinuation<Void, Never>) in }
        preconditionFailure()
    }
}

JadenGeller

@propertyWrapper
struct Versioned<Value>: RandomAccessCollection {
    private var history: [Value]
    
    var startIndex: Int { 0 }
    var endIndex: Int { allValues.endIndex }
    subscript(position: Int) -> Value {
        get { allValues[position] }
        set { allValues[position] = newValue }