mattt

import UIKit

#if canImport(SwiftUI) && DEBUG
import SwiftUI
struct UIViewControllerPreview<ViewController: UIViewController>: UIViewControllerRepresentable {
    let viewController: ViewController

    init(_ builder: @escaping () -> ViewController) {
        viewController = builder()
    }

tclementdev

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

• You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.

• Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

bolencki13

#import <Foundation/Foundation.h>
#import <dlfcn.h>

void logTrace(BOOL on) {
    typedef void functype(BOOL);
    void *libobjc = dlopen("/usr/lib/libobjc.dylib", RTLD_LAZY);
    functype *instrumentObjcMessageSends = dlsym(libobjc, "instrumentObjcMessageSends");
    if (!instrumentObjcMessageSends) {
        NSLog(@"Couldn't get instrumentObjcMessageSends");
        exit(1);

chourobin

Bridging Native & React for iOS & Android

js -> native

• Simple Example
• Callbacks
• Promises
• Properties

native -> js

alanzeino

LLDB Debugging Cheat Sheet

Commands

LLDB Commands

LLDB comes with a great set of commands for powerful debugging.

help

Your starting point for anything. Type help to get a list of all commands, plus any user installed ones. Type 'help for more information on a command. Type help to get help for a specific option in a command too.

kharmabum

/*----------------------------------------------------*/
#pragma mark - XCTAsserts
/*----------------------------------------------------*/

XCTAssert(expression, format...);
XCTAssertTrue(expression, format...);
XCTAssertFalse(expression, format...);
XCTAssertEqual(expression1, expression2, format...);
XCTAssertNotEqual(expression1, expression2, format...);
XCTAssertNil(expression, format...);

jspahrsummers

/// Observes a run loop to detect any stalling or blocking that occurs.
///
/// This class is thread-safe.
@interface GHRunLoopWatchdog : NSObject

/// Initializes the receiver to watch the specified run loop, using a default
/// stalling threshold.
- (id)initWithRunLoop:(CFRunLoopRef)runLoop;

/// Initializes the receiver to detect when the specified run loop blocks for

kopiro

sudo ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future gem install nokogiri -v 1.5.11
sudo gem install nomad-cli

steipete

// Taken from the commercial iOS PDF framework http://pspdfkit.com.
// Copyright (c) 2014 Peter Steinberger, PSPDFKit GmbH. All rights reserved.
// Licensed under MIT (http://opensource.org/licenses/MIT)
//
// You should only use this in debug builds. It doesn't use private API, but I wouldn't ship it.

// PLEASE DUPE rdar://27192338 (https://openradar.appspot.com/27192338) if you would like to see this in UIKit.

#import <objc/runtime.h>
#import <objc/message.h>