Multiline inputs are not possible through code

I have a simple converting script between a custom language and JS

function lexer(code) {
  // lexes code into parts
  const codeParts = [];
  const regex = /"(.*?)"/g; // quote split regex

  const tokens = code.split(regex);

  for (const token of tokens) {
    codeParts.push(token);
  }

  return codeParts;
}

function parse(input) {
  text = input;
  text = text.replace("new", "let");
  text = text.replace("is", "=");
  text = text.replace("say", "console.log");
  text = text.replace("shout", "alert");
  return text;
}

function out(arr) {
  let code = ``;
  for (let i = 0; i < arr.length; i++) {
    if (i % 2 === 0) {
      code = code + parse(arr[i]) + '\n';
    }
    if (i % 2 === 1) {
      code = code + '"' + parse(arr[i]) + '"';
    }
  }
  return code;
}

function convert(input) {
  const codeLex = lexer(input);
  const code = out(codeLex);
  return code;
}

function update(){
    code = '`'+document.getElementById("sparkText").value+'`';
    jsCode = convert(code);
    document.getElementById("jsText").innerHTML = jsCode.substring(1, jsCode.length-2);
}

However, It cant take multiple lines of code, what changes would I have to make for a multiline input and output?

Example

lang 1:

new dog is "dog"
new cat is "cat"

js: let dog = "dog" let cat = "cat"

You can take input from textarea which will allow you for next line (\n) and I think rest below code will do your job

function lexer(code) {
    // lexes code into parts
    const codeParts = [];
    const regex = /"(.*?)"/g; // quote split regex
    const tokens = code.split(regex);
    for (const token of tokens) {
        codeParts.push(token);
    }
    return codeParts;
}

function parse(input) {
    return input.replace("new", "let").replace("is", "=").replace("say", "console.log").replace("shout", "alert");
}
function out(arr) {
    let code = ``;
    for (let i = 0; i < arr.length; i++)
        code += i % 2 === 0 ? parse(arr[i]) : '"' + parse(arr[i]) + '"';
    return code;
}

const input = `new dog is "dog"
new rat is "rat"
new cat is "cat"`


function convertor(input) {
    let output = ``;
    const regex = /\r?\n/; // next line split regex
    const inputs = input.split(regex);
    inputs.forEach(input => {
        output += out(lexer(input)) + "\n"
    });
    return output
}

console.log(convertor(input));