Goldman UI Engineering First Codepad Round First Question.js

/* Problem Name is &&& JS Object to String &&& PLEASE DO NOT REMOVE THIS LINE. */

/**
 * Instructions to candidate:
 *
 *  1) Given the below code. Write a function (ES6 recommended) that loops through all the properties of the Employee and create a comma-seperated string with the values
 *     For e.g.
 *     { 
 *        firstName: "X",
 *        lastName: "Y",
 *        project: {
 *           id: 1,
 *           name: "ABC"
 *         } 
 *     }
 *     should be converted to a string like this "X, Y, 1, ABC, "
 *
 *
 *  NOTE: The function shouldn't convert the prototypically inherited properties For e.g. in this case "managerId"
 *
 */


/**
 * TODO: Write a function here called 'convertToString' that will return the expected result.
 */
function convertToString() {

}

// -----------------------------------

/**
 * Returns true if all tests pass; otherwise, returns false.
 */
function doTestsPass(testCases)
{
  // todo: add more test cases
  return testCases.reduce((result, testCase) => {
    const answer = convertToString(testCase.inputs);
    console.info("expected: ", testCase.expected, ", answer: ", answer);
    return result && (answer === testCase.expected);
  }, true);
}


const testCases = [
  { 
  expected: "Frank, Sinatra, 1, Trader Platform, ",
  inputs: new Employee("Frank", "Sinatra", { id: 1, name: "Trader Platform"})
  }
];

/**
 * Main execution entry.
 */
if(doTestsPass(testCases))
{
  console.log("All tests pass!");
}
else
{
  console.log("There are test failures.");
}

Solution

repl code for the code below

/* Problem Name is &&& JS Object to String &&& PLEASE DO NOT REMOVE THIS LINE. */

/**
 * Instructions to candidate:
 *
 *  1) Given the below code. Write a function (ES6 recommended) that loops through all the properties of the Employee and create a comma-seperated string with the values
 *     For e.g.
 *     { 
 *        firstName: "X",
 *        lastName: "Y",
 *        project: {
 *           id: 1,
 *           name: "ABC"
 *         } 
 *     }
 *     should be converted to a string like this "X, Y, 1, ABC, "
 *
 *
 *  NOTE: The function shouldn't convert the prototypically inherited properties For e.g. in this case "managerId"
 *
 */
const Employee = function (fName, lName, project) {
  this.firstName = fName;
  this.lastName = lName;
  this.project = project;

  this.getFullName = function () {
  return this.lastName + ", " + this.firstName;
  }
};
Employee.prototype.managerId = 123;
Employee.prototype.sayHello = function () {
  console.log("Hello");
};
// ---------------------------------------------

// -------------- write your code here -----------------
function isNonNullable(val) {
  return (val !== null) && (val !== undefined)
}

function isPlainObject(val) {
  const typeIsOfTypeObject =  typeof val === 'object';
  const objectIsJavascriptObject = Object.prototype.toString.call(val) === '[object Object]';

  return typeIsOfTypeObject
    && objectIsJavascriptObject
    && isNonNullable(val);
}


function isFunc(val) {
  return Object.prototype.toString.call(val) === '[object Function]' && isNonNullable(val);
}

/**
 * TODO: Write a function here called 'convertToString' that will return the expected result.
 */
function convertToString(obj, i = 0) {
  function recursiveIterator(employeeObj, index = 0) {
     /* since we are using Object.keys, we automatically
      * take care of the `The function shouldn't convert the prototypically inherited properties For e.g. in this case "managerId"`
      * part in the question. Refer `Object.keys ` mdn docs for why that is
     */
      const keys = Object.keys(employeeObj);

      const retVal = keys.reduce((collector, key) => {
      const val = employeeObj[key];

      /**
       * if it's a function we don't want to do anything with it
       * so we just return the collector array
       */
      if (isFunc(val)) {
        return collector;
      }

      /**
       * if it's a plain javascript object, we need to recurse
       */
      if (isPlainObject(val)) {
        /**
         * the index is just a count of the number of times
         * `recursiveIterator` is called. It's just for debugging
         * purposes. As you can see that we aren't using it anywhere,
         * but just increasing it for every `recursiveIterator` call
         */
        const nextIndex = index ? ++index: 1;

        /**
         * if it's an object, we need to recurse
         * and we need to concat the return value
         * into our collector array. If you don't know
         * how recursion works, you would need to 
         * understand that a little better.
         */
        return collector.concat(recursiveIterator(val, nextIndex));
      }
    
      return collector.concat(val);
    }, [])

    return retVal;
  }

  const finalRetVal = recursiveIterator(obj, i);

  const finalString = finalRetVal.join(', ') + ', '; // just to make the tests work (🤷🏽‍♂️)
  
  return finalString;
}

// -------- END of code that needs to be written ---------------
/**
 * Returns true if all tests pass; otherwise, returns false.
 */
function doTestsPass(testCases)
{
  // todo: add more test cases
  return testCases.reduce((result, testCase) => {
    const answer = convertToString(testCase.inputs);
    console.info("expected: ", testCase.expected, ", answer: ", answer);
    return result && (answer === testCase.expected);
  }, true);
}


const testCases = [
  { 
  expected: "Frank, Sinatra, 1, Trader Platform, ",
  inputs: new Employee("Frank", "Sinatra", { id: 1, name: "Trader Platform"})
  }
];

/**
 * Main execution entry.
 */
if(doTestsPass(testCases))
{
  console.log("All tests pass!");
}
else
{
  console.log("There are test failures.");
}

If you read this and report any unhandled use case, or any error, please feel free to tell that in the comments, so that I can update the solution with it :)

If you find this solution helpful, kindly star the gist :)