StringToBrainfuck.js

/**
 * StringToBrainfuck.js
 *
 * Converts a string to a Brainfuck script that will output said string.
 * usage: node StringToBrainfuck.js your string here
 *
 * @author Maxamilian Demian <max@maxdemian.com>
 * @link https://www.maxodev.org
 * @link https://github.com/Maxoplata/StringToBrainfuck
 */

// if we have arguments passed to the script
if (process.argv.length > 2) {
	const inputString = process.argv.splice(2).join(' ');

	// the Brainfuck code we will output in the end
	let bfCode = '';

	/**
	 * our current location on the "tape" (pointer 1).
	 * we use pointer 0 as a multiplier for pointer 1 to shorten the output script.
	 *
	 * e.g.
	 * A(65) = ++++++[>++++++++++<-]>+++++.
	 * ++++++      = add 6 to current pointer value (pointer 0)
	 * [           = while current pointer (pointer 0)'s value > 0
	 * >           = move pointer ahead one (to pointer 1)
	 * ++++++++++  = add 10 to current pointer value (pointer 1)
	 * <           = move pointer back one (to pointer 0)
	 * -           = subtract 1 from current pointervalue (pointer 0)
	 * ]           = end while loop
	 * >           = move pointer ahead one (to pointer 1)
	 * +++++       = add 5 to current pointer value (pointer 1)
	 * .           = print out character at current pointer value (pointer 1, value 65, char 'A')
	 *
	 * instead of:
	 * +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.
	 */
	let currentLocation = 0;

	// iterate through each character in the string
	[...inputString].forEach((char, i) => {
		// get the Unicode code for the current character
		const charVal = char.charCodeAt(0);

		if (charVal > currentLocation) {
			// move ahead on the "tape" to build the character
			bfCode += '+'.repeat(Math.floor((charVal - currentLocation) / 10));
			bfCode += '[>++++++++++<-]>';
			bfCode += '+'.repeat((charVal - currentLocation) % 10);
		} else if (charVal < currentLocation) {
			// move backwards on the "tape" to build the character
			bfCode += '+'.repeat(Math.floor((currentLocation - charVal) / 10));
			bfCode += '[>----------<-]>';
			bfCode += '-'.repeat((currentLocation - charVal) % 10);
		} else {
			// delete the "<" from the previous command as we are on the same character
			// and we will want to print it out again
			bfCode = bfCode.slice(0, -1);
		}

		// print out the current character
		bfCode += '.';

		// if we are not on the last letter of the string, move pointer position back to 0
		if (i < (inputString.length - 1)) {
			bfCode += '<';
		}

		currentLocation = charVal;
	});

	console.log(bfCode);
}