Scream Cipher

scream.js

// https://xkcd.com/3054/
function scream(input, padChars = false) {
	let keyE = {
		"A": "A",
		"B": "Ȧ",
		"C": "A̧",
		"D": "A̠",
		"E": "Á",
		"F": "A̮",
		"G": "A̋",
		"H": "A̰",
		"I": "Ả",
		"J": "A̓",
		"K": "Ạ",
		"L": "Ă",
		"M": "Ǎ",
		"N": "Â",
		"O": "Å",
		"P": "A̯",
		"Q": "A̤",
		"R": "Ȃ",
		"S": "Ã",
		"T": "Ā", //Wasn't sure if it was 'Ā' or 'A̅' so I just copied Ā from the panel's hover text
		"U": "Ä",
		"V": "À",
		"W": "Ȁ",
		"X": "A̽",
		"Y": "A̦",
		"Z": "A̷"  //Could be 'A̸' or 'A̷', im guessing it's A̷
	};
	let keyD = {
		//Add those uncertain keys to the decoder
		"A̸": "Z",
		"A̅": "T",
		//Add decoding support for some other implementations that avoid combining characters (even though they are used in the panel's hover text)
		"Ȧ": "B",
		"Á": "E",
		"Ả": "I",
		"Ạ": "K",
		"Ă": "L",
		"Ǎ": "M",
		"Â": "N",
		"Å": "O",
		"Ȃ": "R",
		"Ã": "S",
		"Ā": "T",
		"Ä": "U",
		"À": "V",
		"Ȁ": "W",
		"Ⱥ": "Z",
		//Have seen some other people also use these characters instead
		"A̱": "D",
		"A̲": "D",
		"Aͯ": "X",
		"A̡": "C"
	};
	//Use the encoder key to fill out the rest of the decoder key
	for (let i = 0, tmp = Object.keys(keyE); i < tmp.length; i++) {
		keyD[keyE[tmp[i]]] = tmp[i];

		//This seems to slightly improve the chances of an encoded message not getting obliterated when sent in discord
		if (padChars && tmp[i] != "A") {
			keyE[tmp[i]] += '​';
		}
	}

	//Too lazy to check if it should be encoded or decoded so we just do both
	let eOut = "";
	let dOut = "";
	let splitIn = input.toUpperCase().split("");
	for (let i = 0; i < splitIn.length; i++) {

		//If input is in dictionary add value, otherwise add input
		eOut += (keyE[splitIn[i]] != undefined) ? keyE[splitIn[i]] : splitIn[i];
		//If the input is 'A' then we need to check the next character before assuming it's just an 'A'
		if (splitIn[i] == "A") {
			let tmp = splitIn[i] + splitIn[i + 1];
			if (keyD[tmp] != undefined) {
				dOut += keyD[tmp];
				//Increment the index by 1 to skip over the combining character on the next loop
				i++;
				//But make sure the skipped char is still encoded to prevent a message from being corrupted if it's encoded a second time
				eOut += (keyE[splitIn[i]] != undefined) ? keyE[splitIn[i]] : splitIn[i];
			} else {
				dOut += "A";
			}
		} else {
			dOut += (keyD[splitIn[i]] != undefined) ? keyD[splitIn[i]] : splitIn[i];
		}
		
	}
	return {encoded: eOut, decoded: dOut};
}
console.log("scream.js loaded, use scream(\"input\") in your code!\nwritten by FrostBird347, licensed under MIT");

console.log(scream("test message").encoded);
console.log(scream("ĀÁÃĀ ǍÁÃÃAA̋Á").decoded);

Example page: https://frostbird347.bitbucket.io/db/scream.js