Functional Programming Spreadsheet

--- id: 646d47c8f58107d10f1e5106 title: Step 94 challengeType: 0 dashedName: step-94 --- # --description-- The first argument for your `evalFormula` call needs to be the contents of the cell (which you stored in `value`). However, the contents start with an `=` character to trigger the function, so you need to pass the substring of `value` starting at index `1`. # --hints-- You should pass `value` as the first argument to your `evalFormula()` call. ```js assert.match(code, /const\s+update\s*=\s*(?:\(\s*event\s*\)|event)\s*=>\s*\{\s*const\s+element\s*=\s*event\.target\s*;?\s*const\s+value\s*=\s*element\.value\.replace\(\s*\/\\s\/g\s*,\s*('|"|`)\1\s*\)\s*;?\s*if\s*\(\s*(!value\.includes\(\s*element\.id\s*\)\s*&&\s*(?:value\s*\[\s*0\s*\]\s*===\s*('|"|`)=\3|value\.charAt\(\s*0\s*\)\s*===\s*('|"|`)=\4|value\.startsWith\(\s*('|"|`)=\5\s*\))|(?:value\s*\[\s*0\s*\]\s*===\s*('|"|`)=\6|value\.charAt\(\s*0\s*\)\s*===\s*('|"|`)=\7|value\.startsWith\(\s*('|"|`)=\8\s*\))\s*\|\|\s*!value\.includes\(\s*element\.id\s*\))\s*\)\s*\{\s*element\.value\s*=\s*evalFormula\(\s*value/); ``` You should call the `.slice()` method on the `value` argument. ```js assert.match(code, /const\s+update\s*=\s*(?:\(\s*event\s*\)|event)\s*=>\s*\{\s*const\s+element\s*=\s*event\.target\s*;?\s*const\s+value\s*=\s*element\.value\.replace\(\s*\/\\s\/g\s*,\s*('|"|`)\1\s*\)\s*;?\s*if\s*\(\s*(!value\.includes\(\s*element\.id\s*\)\s*&&\s*(?:value\s*\[\s*0\s*\]\s*===\s*('|"|`)=\3|value\.charAt\(\s*0\s*\)\s*===\s*('|"|`)=\4|value\.startsWith\(\s*('|"|`)=\5\s*\))|(?:value\s*\[\s*0\s*\]\s*===\s*('|"|`)=\6|value\.charAt\(\s*0\s*\)\s*===\s*('|"|`)=\7|value\.startsWith\(\s*('|"|`)=\8\s*\))\s*\|\|\s*!value\.includes\(\s*element\.id\s*\))\s*\)\s*\{\s*element\.value\s*=\s*evalFormula\(\s*value\.(?:slice|substring)\(/); ``` You should pass the number `1` as the argument to your `.slice()` call. ```js assert.match(code, /const\s+update\s*=\s*(?:\(\s*event\s*\)|event)\s*=>\s*\{\s*const\s+element\s*=\s*event\.target\s*;?\s*const\s+value\s*=\s*element\.value\.replace\(\s*\/\\s\/g\s*,\s*('|"|`)\1\s*\)\s*;?\s*if\s*\(\s*(!value\.includes\(\s*element\.id\s*\)\s*&&\s*(?:value\s*\[\s*0\s*\]\s*===\s*('|"|`)=\3|value\.charAt\(\s*0\s*\)\s*===\s*('|"|`)=\4|value\.startsWith\(\s*('|"|`)=\5\s*\))|(?:value\s*\[\s*0\s*\]\s*===\s*('|"|`)=\6|value\.charAt\(\s*0\s*\)\s*===\s*('|"|`)=\7|value\.startsWith\(\s*('|"|`)=\8\s*\))\s*\|\|\s*!value\.includes\(\s*element\.id\s*\))\s*\)\s*\{\s*element\.value\s*=\s*evalFormula\(\s*value\.(?:slice|substring)\(\s*1\s*\)\s*\)\s*;?/); ``` # --seed-- ## --seed-contents-- ```html Functional Programming Spreadsheet

``` ```css #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; } ``` ```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)]; } const spreadsheetFunctions = { sum, average, median } 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)); return str2.replace(functionCall, (match, fn, args) => spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()) ? apply(fn, args) : match); } 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 functionExpanded = applyFunction(cellExpanded); return functionExpanded === x ? functionExpanded : evalFormula(functionExpanded, cells); } 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); }) }) } --fcc-editable-region-- const update = event => { const element = event.target; const value = element.value.replace(/\s/g, ""); if (!value.includes(element.id) && value.startsWith('=')) { element.value = evalFormula(); } } --fcc-editable-region-- ```