Expo: iOS background delivery is implemented in a brittle way

[jhogervorst]

I see that the setup of background delivery for iOS in your Expo plugin was done in a brittle way (by manually patching the app delegate file):

terra-react/plugin/src/index.ts

Lines 7 to 53 in 1536fc2

	const withTerraBackgroundDelivery: ConfigPlugin = (config) => {
	config = withAppDelegate(config, (delegateConfig) => {
	const { contents } = delegateConfig.modResults;
	if (delegateConfig.modResults.language === 'swift') {
	if (!delegateConfig.modResults.contents.includes('import TerraiOS')) {
	delegateConfig.modResults.contents =
	`import TerraiOS\n` + delegateConfig.modResults.contents;
	}
	if (
	!delegateConfig.modResults.contents.includes(
	'Terra.setUpBackgroundDelivery()'
	)
	) {
	const regex =
	/return super.application\(application, didFinishLaunchingWithOptions: launchOptions\)/;
	delegateConfig.modResults.contents =
	delegateConfig.modResults.contents.replace(
	regex,
	(match) => `Terra.setUpBackgroundDelivery()\n ${match}`
	);
	}
	} else {
	if (!contents.includes('#import <TerraiOS/TerraiOS-Swift.h>')) {
	delegateConfig.modResults.contents = contents.replace(
	'#import "AppDelegate.h"',
	'#import "AppDelegate.h"\n#import <TerraiOS/TerraiOS-Swift.h>'
	);
	}
	if (!contents.includes('[Terra setUpBackgroundDelivery];')) {
	const regex =
	/- \(BOOL\)application:\(UIApplication \*\)application didFinishLaunchingWithOptions:\(NSDictionary \*\)launchOptions\s*\{\n/;
	delegateConfig.modResults.contents =
	delegateConfig.modResults.contents.replace(
	regex,
	(match) => `${match} [Terra setUpBackgroundDelivery];\n`
	);
	}
	}
	return delegateConfig;
	});
	return config;
	};

I believe that Expo has a better way (docs) for this.

I actually implemented that in my custom Terra Expo plugin, which I created before you guys offered one: app delegate, config.

Maybe this could be improved in your Expo plugin. (Feel free to reuse my code!)