freeCodeCamp/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-functional-programming-by-building-a-spreadsheet/6449876e7aae0d2f8257a497.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6449876e7aae0d2f8257a497	Step 41	0	step-41

--description--

Declare a rangeFromString arrow function that takes two parameters, num1 and num2. The function should implicitly return the result of calling range with num1 and num2 as arguments.

To be safe, parse num1 and num2 into integers as you pass them into range.

--hints--

You should declare a rangeFromString variable after your rangeRegex.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*(?:var|let|const)\s+rangeFromString/);

You should use const to declare your rangeFromString variable.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString/);

Your rangeFromString variable should be an arrow function.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString\s*=\s*\(.*\)\s*=>/);

Your rangeFromString function should have num1 as the first parameter.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString\s*=\s*\(\s*num1/);

Your rangeFromString function should have num2 as the second parameter.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString\s*=\s*\(\s*num1\s*,\s*num2\s*\)\s*=>/);

Your rangeFromString function should use an implicit return.

assert.notMatch(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString\s*=\s*\(\s*num1\s*,\s*num2\s*\)\s*=>\s*\{/);

Your rangeFromString function should return the result of calling your range function.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString\s*=\s*\(\s*num1\s*,\s*num2\s*\)\s*=>\s*range\(/);

You should call parseInt with num1 as an argument and pass the result to the range call.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString\s*=\s*\(\s*num1\s*,\s*num2\s*\)\s*=>\s*range\(\s*parseInt\(\s*num1\s*\)/);

You should call parseInt with num2 as the argument and pass the result to the range call.

assert.match(code, /const\s+evalFormula\s*=\s*\(\s*x\s*,\s*cells\s*\)\s*=>\s*{\s*const\s+idToText\s*=\s*(\(\s*id\s*\)|id)\s*=>\s*cells\.find\(\s*(\(\s*cell\s*\)|cell)\s*=>\s*(?:cell\.id\s*===\s*id|id\s*===\s*cell\.id)\s*\)\.value\s*;?\s*const\s+rangeRegex\s*=\s*\/\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\):\(\[A-J\]\)\(\[1-9\]\[0-9\]\?\)\/(gi|ig)\s*;?\s*const\s+rangeFromString\s*=\s*\(\s*num1\s*,\s*num2\s*\)\s*=>\s*range\(\s*parseInt\(\s*num1\s*\)\s*,\s*parseInt\(\s*num2\s*\)\s*\)/);

--seed--

--seed-contents--

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link rel="stylesheet" href="./styles.css" />
    <title>Functional Programming Spreadsheet</title>
  </head>
  <body>
    <div id="container">
      <div></div>
    </div>
    <script src="./script.js"></script>
  </body>
</html>

#container {
  display: grid;
  grid-template-columns: 50px repeat(10, 200px);
  grid-template-rows: repeat(11, 30px);
}

.label {
  background-color: lightgray;
  text-align: center;
  vertical-align: middle;
  line-height: 30px;
}

const isEven = num => num % 2 === 0;
const sum = nums => nums.reduce((acc, el) => acc + el, 0);
const average = nums => sum(nums) / nums.length;

const median = nums => {
  const sorted = nums.slice().sort((a, b) => a - b);
  const length = sorted.length;
  const middle = length / 2 - 1;
  return isEven(length)
    ? average([sorted[middle], sorted[middle + 1]])
    : sorted[Math.ceil(middle)];
}

const spreadsheetFunctions = {
  sum,
  average,
  median
}

const range = (start, end) => Array(end - start + 1).fill(start).map((element, index) => element + index);
const charRange = (start, end) => range(start.charCodeAt(0), end.charCodeAt(0)).map(code => String.fromCharCode(code));

--fcc-editable-region--
const evalFormula = (x, cells) => {
  const idToText = id => cells.find(cell => cell.id === id).value;
  const rangeRegex = /([A-J])([1-9][0-9]?):([A-J])([1-9][0-9]?)/gi;

}
--fcc-editable-region--

window.onload = () => {
  const container = document.getElementById("container");
  const createLabel = (name) => {
    const label = document.createElement("div");
    label.className = "label";
    label.textContent = name;
    container.appendChild(label);
  }
  const letters = charRange("A", "J");
  letters.forEach(createLabel);
  range(1, 99).forEach(number => {
    createLabel(number);
    letters.forEach(letter => {
      const input = document.createElement("input");
      input.type = "text";
      input.id = letter + number;
      input.ariaLabel = letter + number;
      input.onchange = update;
      container.appendChild(input);
    })
  })
}

const update = event => {
  const element = event.target;
  const value = element.value.replace(/\s/g, "");
  if (!value.includes(element.id) && value.startsWith('=')) {

  }
}