Brainfuck.js

branfuck.js

function branfuck(code, input){
  const output = [];
  const data = [];
  let dataPointer = 0;
  let inputPointer = 0;
  let inputArr = input.split('').map(i => i.codePointAt(0))
  const chars = code.split('');
  let codePointer = 0;

  
  while(codePointer < chars.length) {
    let c = chars[codePointer];
    switch(c) {
      case '>':
        dataPointer++;
        break;
      case '<':
        dataPointer--;
        break;
      case '+': {
        if (!data[dataPointer]) {
          data[dataPointer] = 0;
        }
        data[dataPointer]++;
        if (data[dataPointer] === 256) {
          data[dataPointer] = 0;
        }
        break;
      }
      case '-': {
        if (!data[dataPointer]) {
          data[dataPointer] = 0;
        }
        data[dataPointer]--;
        if (data[dataPointer] === -1) {
          data[dataPointer] = 255;
        }
        break;
      }
      case '.':
        output.push(data[dataPointer]);
        break;
      case ',':
        data[dataPointer] = inputArr[inputPointer];
        inputPointer++;
        break;
      case '[':
         if (!data[dataPointer]) {
            let depth = 1;
            while (depth > 0) {
              codePointer++;
              if (chars[codePointer] === '[') {
                depth++;
              } else if (chars[codePointer] === ']') {
                depth--;
              }
            }
         }
        break;
      case ']':
        if (data[dataPointer] > 0) {
          let depth = 1;
          while (depth > 0) {
            codePointer--;
            if (chars[codePointer] === '[') {
              depth--;
            } else if (chars[codePointer] === ']') {
              depth++;
            }
          }
        }
    }
    codePointer++;
  }
  return output.map(c => String.fromCharCode(c)).join('');
}