Evolution of Promise syntax

evolutionOfPromise.js

const originalFunctionWithPromise = (num) => new Promise((resolve, reject) => {
  try {
    if (typeof num !== 'number') {
      return reject(new Error('Invalid input'));
    }
    return resolve(5 * num);
  } catch (err) {
    return reject(err);
  }
});

const originalFunction = async (num) => {
  try {
    if (typeof num !== 'number') {
      throw new Error('Invalid input');
    }
    return (5 * num);
  } catch (someError) {
    throw someError;
  }
};

const modifiedFunction = async (num1, num2) => {
  if (typeof num1 !== 'number' || typeof num2 !== 'number') {
    throw new Error('INVALID_INPUT');
  }
  return (10 * num1 * num2);
};

const errorHandler = fn => async (...args) => {
  try {
    const res = await fn(...args);
    return res;
  } catch (someError) {
    throw someError;
  }
};

const differentErrorHandler = fn => async (...args) => {
  try {
    const res = await fn(...args);
    return res;
  } catch (someError) {
    if (someError.message === 'INVALID_INPUT') {
      const InvalidInputError = new Error('Maybe try using a number next time');
      throw InvalidInputError;
    }
    throw someError;
  }
};

const modifiedFunctionWithErrorHandling = errorHandler(modifiedFunction);
const modifiedFunctionWithDifferentErrorHandling = differentErrorHandler(modifiedFunction);

async function init() {
  try {
    const result1 = await modifiedFunctionWithErrorHandling(3, 2);
    console.log('Result 1 :', result1);
    const result2 = await modifiedFunctionWithErrorHandling('chinmay', 2);
    console.log('Result 2 :', result2);
  } catch (err) {
    console.error('Simple Error:', err.message);
  }
  try {
    const result3 = await modifiedFunctionWithDifferentErrorHandling('chinmay', 2);
    console.log('Result 3: ', result3);
  } catch (err) {
    console.error('Different Error: ', err.message);
  }
}

init();