# Learn Functional Programming by Building a Spreadsheet - Step 87

### Tell us what’s happening:

I genuinely don’t know what I’m supposed to do here. Obviously I’m doing something wrong. Here are the instructions: “Your apply function is returning the spreadsheet function, but not actually applying it. Update apply to call the function. Pass in the result of calling toNumberList with args as an argument. " I don’t even understand what the problem is. I added {} and “return” to see if that would work. It didn’t. Error message reads, " Your apply function should call the spreadsheetFunctions[fn.toLowerCase()] function.” EDIT: I realized I’m supposed to add toNumberList(args) but I’m not adding it the right way. Console error reads: // running tests Your apply function should call the spreadsheetFunctions[fn.toLowerCase()] function. You should pass a toNumberList() call to your spreadsheetFunctions[fn.toLowerCase()] call. You should pass args to your toNumberList() call. // tests completed

/* file: script.js */
const infixToFunction = {
"+": (x, y) => x + y,
"-": (x, y) => x - y,
"*": (x, y) => x * y,
"/": (x, y) => x / y,
}

const infixEval = (str, regex) => str.replace(regex, (_match, arg1, operator, arg2) => infixToFunction[operator](parseFloat(arg1), parseFloat(arg2)));

const highPrecedence = str => {
const regex = /([\d.]+)([*\/])([\d.]+)/;
const str2 = infixEval(str, regex);
return str === str2 ? str : highPrecedence(str2);
}

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)];
}

sum,
average,
median
}

// User Editable Region

const applyFunction = str => {
const noHigh = highPrecedence(str);
const infix = /([\d.]+)([+-])([\d.]+)/;
const str2 = infixEval(noHigh, infix);
const functionCall = /([a-z0-9]*)\(([0-9., ]*)\)(?!.*\()/i;
const toNumberList = args => args.split(",").map(parseFloat);
const apply = (fn, args) => spreadsheetFunctions[fn.toLowerCase()].toNumberList(args);

}

// User Editable Region

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));

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;
const rangeFromString = (num1, num2) => range(parseInt(num1), parseInt(num2));
const elemValue = num => character => idToText(character + num);
const addCharacters = character1 => character2 => num => charRange(character1, character2).map(elemValue(num));
const rangeExpanded = x.replace(rangeRegex, (_match, char1, num1, char2, num2) => rangeFromString(num1, num2).map(addCharacters(char1)(char2)));
const cellRegex = /[A-J][1-9][0-9]?/gi;
const cellExpanded = rangeExpanded.replace(cellRegex, match => idToText(match.toUpperCase()));
}

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('=')) {

}
}