Hwee-Boon Yar hboon

Found a bug in my code because of something very subtle:

class C: NSObject {
	var foo: String = {
		NSLog("non-lazy self: \(self)")
		return ""
	}()
	lazy var bar: String = {
 NSLog("lazy self: \(self)")

JavaScriptCore is a built-in iOS library that enables you to use JavaScript in apps alongside Objective-C and Swift. It lets developers read JavaScript from a string, execute it from Objective-C or Swift, and share data structures and functions across languages. We JavaScriptCore to share code between Web and iOS.

Sharing code helped us produce a high-quality, consistent experience across devices while iterating rapidly.

This post is about why we chose to use JavaScriptCore and what we learned. The biggest challenges to using JavaScriptCore in a production app were performance optimization for older devices and getting the build process right. Luckily, these problems have simple solutions that just weren't documented.

Why did we use JavaScriptCore?

A killer feature of one of our apps is search that is optimized for finding guests by name. Our goals included:

6 Feb

Location: Home Notes: Productive with 0 pomodoros

11:04 PM - 11:07 PM Plan 11:10 PM Mimic

::Mimic

	#!/bin/sh

	if git rev-parse --verify HEAD >/dev/null 2>&1; then
	against=HEAD
	else
	# Initial commit: diff against an empty tree object
	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
	fi

	exec 1>&2

	* TokenScript repo is up
	* Main homepage is up
	* Verify sig API is up and working
	* Check express of trust API is up and working
	* Any other API is up
	* Any other important site is up

	// The trick is to link the DeviceSupport folder from the beta to the stable version.
	// sudo needed if you run the Mac App Store version. Always download the dmg instead... you'll thank me later :)

	// Xcode 10.2 to Xcode 11 Beta
	sudo ln -s /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/13.0 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport

	// Then restart Xcode and reconnect your devices. You will need to do that for every beta of future iOS versions

	import Foundation
	import WebKit

	final class WebCacheCleaner {

	class func clean() {
	HTTPCookieStorage.shared.removeCookies(since: Date.distantPast)
	print("[WebCacheCleaner] All cookies deleted")

	WKWebsiteDataStore.default().fetchDataRecords(ofTypes: WKWebsiteDataStore.allWebsiteDataTypes()) { records in

	let abi = {
	"name" : "balanceOf",
	"stateMutability" : "view",
	"outputs" : [
	],
	"inputs" : [
	{
	"name" : "expiry",
	"type" : "uint256"
	},

	Found a bug in my code because of something very subtle:

	```
	class C: NSObject {
	var foo: String = {
	NSLog("non-lazy self: \(self)")
	return ""
	}()
	lazy var bar: String = {
	NSLog("lazy self: \(self)")

	1. Check that in `/token/origins/<ethereum contract="holdingContract">` the string `holdingContract` refers to an existing contract defined in `/token/contract`

	ref: https://github.com/AlphaWallet/alpha-wallet-ios/issues/1440