Callback Hell

	// callback-hell.js
	const fs = require('fs');
	fs.readFile('a.txt', function(err, dataA) {
	if(err) console.error(err);
	fs.readFile('b.txt', function(err, dataB) {
	if(err) console.error(err);
	fs.readFile('c.txt', function(err, dataC) {
	if(err) console.error(err);
	setTimeout(function() {
	fs.writeFile('d.txt', dataA+dataB+dataC, function(err) {
	if(err) console.error(err);
	});
	}, 60*1000);
	});
	});
	});
	// const fs = require('fs');
	function readSketchyFile() {
	try {
	fs.readFile('does_not_exist.txt', function(err, data) {
	if(err) throw err;
	});
	} catch(err) {
	console.log('warning: minor issue occurred, program continuing');
	}
	}
	readSketchyFile();

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