main.js

const toast = document.getElementById('toast');
const runButton = document.getElementById('runbutton');
const indentDisplay = document.getElementById('indentdisplay');
const textarea = document.getElementById('pseudocode');
const output = document.getElementById('output');
const errorDisplay = document.getElementById('error');

const examples = [
  `Read x
Print x`,
  `Set i to 1
While (i <= 10)
    Print i
    Set i to i + 1`,
  `Set i to 1
While (i <= 100)
    If (i % 15 = 0)
        Print "FizzBuzz"
    ElseIf (i % 3 = 0)
        Print "Fizz"
    ElseIf (i % 5 = 0)
        Print "Buzz"
    Else
        Print i
    Set i to i + 1`,
  `Function fact(n)
    If (n = 0)
        Return 1
    Return n * fact(n - 1)

Read num "Enter a number"
Print fact(num)`,
];

document.addEventListener('keydown', (evt) => {
  if (evt.keyCode === 13 && evt.ctrlKey) {
    runButton.onclick();
  }
});

let indent = '    ';

let jscode;
let saveIndentLevel;

const indexOfEnd = (str, elt) => {
  let index = str.indexOf(elt);

  if (index === -1) {
    index = str.length;
  }

  return index;
};

const choose = (arr) => {
  const index = Math.floor(Math.random() * arr.length);
  return arr[index];
};

// eslint-disable-next-line no-unused-vars
const IsEmpty = arr => arr.length === 0;

// eslint-disable-next-line no-unused-vars
const Push = (arr, value) => {
  arr.push(value);
};

// eslint-disable-next-line no-unused-vars
const Pop = arr => arr.pop();

// eslint-disable-next-line no-unused-vars
const Enque = (arr, value) => {
  Push(arr, value);
};

// eslint-disable-next-line no-unused-vars
const Deque = arr => arr.shift();

// eslint-disable-next-line no-unused-vars
const Insert = (arr, value) => {
  Push(arr, value);
};

// eslint-disable-next-line no-unused-vars
const Delete = (arr, value) => {
  const index = arr.indexOf(value);

  if (index !== -1) {
    arr.splice(index, 1);
  }
};

// eslint-disable-next-line no-unused-vars
const IsThere = (arr, value) => arr.indexOf(value) !== -1;

const setIndent = (newIndentSize) => {
  indent = '';

  for (let i = 0; i < newIndentSize; i++) {
    indent += ' ';
  }

  indentDisplay.innerHTML = newIndentSize;
};

const reindent = (indentSize) => {
  const saveIndent = indent;
  const lines = textarea.value.split('\n');
  let newText = '';

  setIndent(indentSize);

  for (let i = 0; i < lines.length; i++) {
    let currentIndentLevel = 0;

    while (lines[i].includes(saveIndent)) {
      currentIndentLevel++;
      lines[i] = lines[i].replace(saveIndent, '');
    }

    while (currentIndentLevel > 0) {
      currentIndentLevel--;
      lines[i] = indent + lines[i];
    }

    newText += lines[i];

    if (i < lines.length - 1) {
      newText += '\n';
    }
  }

  textarea.value = newText;
};

// eslint-disable-next-line no-unused-vars
const chooseExample = (i) => {
  const prevIndent = indent.length;
  setIndent(4);
  textarea.value = examples[i];
  reindent(prevIndent);
};

const displayError = (error) => {
  errorDisplay.innerHTML = error;
  throw error;
};

const convertLine = (line) => {
  const firstWS = indexOfEnd(line, ' ');
  const lineConvert = line.substring(0, firstWS).toLowerCase() + line.substring(firstWS);
  let rest;

  const lineWords = lineConvert.split(' ');

  switch (lineWords[0]) {
    case '':
      break;

    case 'set':
      rest = line.substring(line.indexOf('to ') + 3);
      jscode += `${lineWords[1]} = ${rest}\n`;
      break;

    case 'get':
    case 'read':
    case 'input':
      rest = line.substring(indexOfEnd(line, lineWords[2])).replace(/['"]/g, '');
      jscode += `reserve = prompt('${rest}' || 'Enter Input...')
${lineWords[1]} = +reserve || reserve\n`;
      break;

    case 'print':
    case 'write':
    case 'display':
    case 'output':
      rest = line.substring(line.indexOf(' ') + 1);
      jscode += `output.innerHTML += (${rest}) + "</br>"\n`;
      break;

    case 'if':
    case 'else':
    case 'while':
    case 'function':
      saveIndentLevel++;
      jscode += `${lineConvert.replace('[]', '')} {\n`;
      break;

    case 'elif':
    case 'elseif':
      saveIndentLevel++;
      rest = line.substring(lineConvert.indexOf('if ') + 3);
      jscode += `else if ${rest} {\n`;
      break;

    case 'return':
      jscode += `${lineConvert}\n`;
      break;

    case 'array':
    case 'boolean':
    case 'integer':
    case 'float':
    case 'string':
      rest = line
        .substring(line.indexOf(' ') + 1)
        .replace('[', '= new Array(')
        .replace(']', ')');
      jscode += `${rest}\n`;
      break;

    case 'increment':
      rest = line.substring(line.indexOf(' ') + 1);
      jscode += `${rest}++\n`;
      break;

    case 'decrement':
      rest = line.substring(line.indexOf(' ') + 1);
      jscode += `${rest}--\n`;
      break;

    default:
      if (lineWords[1] === '<--') {
        rest = line.substring(line.indexOf('<--') + 3);
        jscode += `${line.substring(0, line.indexOf(' '))} =${rest}\n`;
      } else {
        jscode += `${line}\n`;
      }
  }
};

runButton.onclick = () => {
  output.innerHTML = '';
  errorDisplay.innerHTML = '';

  const lines = textarea.value.split('\n');

  jscode = '';
  saveIndentLevel = 0;
  let lastIndentLevel = 0;

  for (let i = 0; i < lines.length; i++) {
    let currentIndentLevel = 0;

    let line = lines[i];

    while (line.charAt(0) === ' ') {
      if (line.includes(indent)) {
        currentIndentLevel++;
        line = line.replace(indent, '');
      } else {
        displayError(new Error(`Indentation mismatch on line ${i + 1}`));
      }
    }

    if (currentIndentLevel - lastIndentLevel >= 2) {
      displayError(new Error(`Unexpected indentation on line ${i + 1}`));
    }

    lastIndentLevel = currentIndentLevel;

    while (currentIndentLevel < saveIndentLevel) {
      saveIndentLevel--;
      jscode += '}\n';
    }

    line = line
      .substring(0, indexOfEnd(line, '//'))
      .replace(/[(]/g, ' (')
      .replace(/else if/i, 'else if')
      .replace(/true/gi, 'true')
      .replace(/false/gi, 'false')
      .replace(/ and /gi, ' && ')
      .replace(/ or /gi, ' || ')
      .replace(/[(]not /gi, '(!')
      .replace(/ not /gi, ' !')
      .replace(/=/g, '==')
      .replace(/ equals /gi, ' == ')
      .replace(/ is equal to /gi, ' == ')
      .replace(/!==/g, '!=')
      .replace(/ is not equal to /gi, ' != ')
      .replace(/ does not equal /gi, ' != ')
      .replace(/<==/g, '<=')
      .replace(/ is less than /gi, ' <= ')
      .replace(/>==/g, '>=')
      .replace(/ is greater than /gi, ' >= ');
    convertLine(line);
  }

  while (saveIndentLevel > 0) {
    saveIndentLevel--;
    jscode += '}\n';
  }

  console.log(`--- START OF CONVERTED JAVASCRIPT CODE ---

${jscode}
---  END OF CONVERTED JAVASCRIPT CODE  ---`);

  try {
    eval(jscode);
  } catch (e) {
    displayError(e);
  }
};

if (Math.random() < 0.5) {
  toast.innerHTML = choose([
    'Now with 20% less fat',
    'How was the midterm?',
    'If there\'s a bug I probably won\'t fix it',
    'I\'m great with names',
    'Try Ctrl+Enter',
    'Kinda like Python',
    'Try not to create an infinite loop!',
    'Complex Randy',
    'Add for amity',
    'wtb 20 trout',
    'Who did this?',
    'How do functions break up? They stop calling each other!',
    'How do ships send files? Pier-to-Pier.',
  ]);
} else {
  toast.innerHTML = 'Run pseudocode in the browser';
}