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davbeck / WKUIDelegate.m
Last active September 28, 2023 06:59
Boilerplate implementation of WKUIDelegate to support Javascript alerts.
View WKUIDelegate.m
#pragma mark - WKUIDelegate
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)())completionHandler
UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil
[alert addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"OK", nil) style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
View Expanded.swift
// example of what the macros could be expanded into for XCTestCase
final class PostsCoordinatorTests: XCTestCase {
func test_addPost() async throws {
let coordinator = PostsCoordinator()
XCTAssert(coordinator.postCount == 1)
func test_hasExistingPosts_countsPosts() async throws {
davbeck /
Created June 19, 2019 22:07
A wrapper for UICollectionViewDiffableDataSource that also handles updates to data

UICollectionViewDiffableDataSource does an excellent job of handling changes to data and updating the items accordingly. However, there seems to be no good way to handle updates to existing items. If you follow the samples that Apple provides and define Equatable and Hashable to use an id instead of the complete models value, value changes won't cause the collection view to update those cells. If you leave Equatable as it should be and have it compare all values of a model, the cell will update, but it will completely replace the old cell, causing an undesirable "flash".

UICollectionViewComparableDataSource wraps a UICollectionViewDiffableDataSource and will check for items that have been updated, but not removed or added.

This allows us to make updates to a cell without completely reloading it. This is especially usefull if your cells have some sort of temporary state.

This is just an expirement. Use at your own risk.

davbeck / DisplayLink.swift
Created July 20, 2019 18:42
A Combine Publisher version of CADisplayLink.
View DisplayLink.swift
View Weak.swift
import Foundation
struct Weak<Value: AnyObject> {
weak var value: Value?
init(_ value: Value) {
self.value = value
davbeck / assets.rb
Last active January 18, 2023 01:35
Automatic Enum-based Xcassets in Swift
View assets.rb
#!/usr/bin/env ruby
require "active_support"
def assetCatalogsAtPath(path)
results = []
contents = Dir.entries(path)
View UITask.swift
import UIKit
import Combine
public extension Task {
/// Keep a reference to a task that can be cancelled.
func store(in set: inout Set<AnyCancellable>) {
set.insert(AnyCancellable {
View fetch.swift
func fetch<Result: Codable>(_ endpoint: Endpoint<Result>, cacheBehavior: CacheBehavior = .cacheElseNetwork) async throws -> Result {
switch cacheBehavior {
case .cacheElseNetwork:
if let cached = self.cache[endpoint.cacheKey] {
return cached.payload
} else {
return try await self.networkFetch(endpoint)
case .networkOnly:
return try await self.networkFetch(endpoint)
davbeck / GQL.swift
Created May 2, 2015 15:52
GraphQL data structure implemented in Swift
View GQL.swift
import Foundation
protocol GQLNodeArgument {}
extension String: GQLNodeArgument {}
extension NSNumber: GQLNodeArgument {}
class GQLNode: StringLiteralConvertible, ArrayLiteralConvertible, Printable, DebugPrintable {
let name: String?
View Binding+NilCoalescing.swift
import SwiftUI
func ?? <T>(optional: Binding<T?>, defaultValue: @escaping @autoclosure () -> T) -> Binding<T> {
return Binding {
optional.wrappedValue ?? defaultValue()
} set: { newValue in
optional.wrappedValue = newValue