README.md

Advent of Code 2023

This repository contains my solutions to 2023 Advent of Code. This readme file also contains core JavaScript concepts that I have revised while solving the problems. You can find extensive comments embeded in the code that will help understand key methods used such as: regular expressions, array manipulation, destructing array assignment and JavaScript specific methods such as isNaN(), hasSymbol() and more;

Table of Contents

• Loading files in JS
• Pre-processing
• Arrays

Loading files in JS

const filePath = '~/Desktop/AoC/Advent-of-Code/day5/input.txt';

fs.readFile(filePath, 'utf8', (err, data) => {

    const input = data.split("\n");
    console.log(input);

});

Pre-processing

If there are spaces like this in your input.txt file and you want to separate them based on the empty lines you can use the following code where input[0] will log to the console:

--------------  INPUT:  --------------
seeds: 79 14 55 13

seed-to-soil map:
50 98 2
52 50 48

soil-to-fertilizer map:
0 15 37
37 52 2
39 0 15

--------------  CODE:  --------------
const fs = require('fs');
const filePath = '/Users/ewa.szyszka/Desktop/AoC/Advent-of-Code/day5/input.txt';


fs.readFile(filePath, 'utf8', (err, data) => {

    const input = data.split("\n\n"); //data.split("\n\n") --> This is very useful when you want to split the input data which

    console.log(input[0]);

});

--------------  OUTPUT:  --------------
seeds: 79 14 55 13

Methods

Name	Description	INPUT	CODE	OUTPUT
x.length()
x.map()
x.trim()	Remove white spaces	let x = [ 'seeds:', '79', '14' ]	x.trim()
parseInt()	String --> Integer	let x = [ 'seeds:', '79', '14' ]	parseInt(x)	[ Nan, 79, 14 ]
.filter()		let x = [NaN, 79, 14, 55, 13]	x.filter(i => !isNaN(i))	[ 79, 14 ]
.forEach()		const x = [1, 2, 3, 4, 5]	x.forEach( (i) => console.log(i))	1,2,3,4,5
typoeof	Returns varible type	let myVariable = "LR";	typeof myVariable;	string
setTimeout()	Call back function	let myVariable = "LR";	typeof myVariable;	string
String()	Turns into a string	input = x	String(input)	"x"
.at()	Return charater at an index	const alphabet = "abcd"	alphabet.at(1)	"b"
.substring()	Return a substring	const alphabet = "abcdddd"	alphabet.substring(3,6);	"dddd"
.slice()	Cuts & returns right str	let word = "Yuto Kimura"	word.slice(1)	uto Kimura
constructor()	Cuts & returns right str	let word = "Yuto Kimura"	word.slice(1)	uto Kimura

Operators

Name	Description	INPUT	CODE	OUTPUT
+=	plus eqaul operator	let name = "Sam";	name += " Blue";	"Sam Blue"

JS concepts

Name	Description	INPUT	CODE	OUTPUT
concatenate	adds two things	let A = "A" let B = "B"	A + B	"AB"
+=	plus eqaul operator	let name = "Sam";	name += " Blue";	"Sam Blue"
template string		This is a template string	name += " Blue";	"Sam Blue"
reference vs value		``	``	``
== vs ===		``	``	``
immutability		``	``	``
asynchronous	Multiple processes at the same time	``	``	``
async / await		``	``	``
try / catch		``	``	``
export default function		``	``	``
this		``	``	``

DataStructures: Stacks

nullish coalescing operator

Higher order functions

• Functions that take in or return functions

Arrow functions

• You cannot use them as object constructors

Regular expressions

This regex returns the number from a string:

INPUT: "200px"
OUTPUT: "200"

    return value.match(/\d+/g); <br>
}```

### DataStructures: Arrays

## Destructing assignment in arrays

### DataStructures: Objects