---
id: 5d7925377b54d8a76efb5657
title: Part 89
challengeType: 0
---
## Description
<section id='description'>
Add the following code to `letters.forEach`:
```js
input.type = "text";
input.id = y + x;
input.onchange = update;
container.appendChild(input);
```
</section>
## Instructions
<section id='instructions'>
</section>
## Tests
<section id='tests'>
```yml
tests:
- text: See description above for instructions.
testString: assert(/window\.onload[\s\S]*range\(1,99\)\.forEach\(\(?x\)?=>\{createLabel\(x\);?letters\.forEach\(\(?y\)?=>\{constinput=document\.createElement\(["']input["']\);?input\.type=["']text["'];?input\.id=y\+x;?input\.onchange=update;?container\.appendChild\(input\);?\}\);?\}\);?\}/.test(code.replace(/\s/g, "")));
```
</section>
## Challenge Seed
<section id='challengeSeed'>
<div id='html-seed'>
```html
<script>
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, (_, arg1, fn, arg2) =>
infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
);
const highPrecedence = str => {
const regex = /([0-9.]+)([*\/])([0-9.]+)/;
const str2 = infixEval(str, regex);
return str === str2 ? str : highPrecedence(str2);
};
const spreadsheetFunctions = {
"": x => x
};
const applyFn = str => {
const noHigh = highPrecedence(str);
const infix = /([0-9.]+)([+-])([0-9.]+)/;
const str2 = infixEval(noHigh, infix);
const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
const toNumberList = args => args.split(",").map(parseFloat);
const applyFunction = (fn, args) =>
spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
return str2.replace(
regex,
(match, fn, args) =>
spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()) ? applyFunction(fn, args) : match
);
};
const range = (start, end) =>
start > end ? [] : [start].concat(range(start + 1, end));
const charRange = (start, end) =>
range(start.charCodeAt(0), end.charCodeAt(0)).map(x =>
String.fromCharCode(x)
);
const evalFormula = x => {
const rangeRegex = /([A-J])([1-9][0-9]?):([A-J])([1-9][0-9]?)/gi;
const rangeFromString = (n1, n2) => range(parseInt(n1), parseInt(n2));
const elemValue = n => c => document.getElementById(c + n).value;
const addChars = c1 => c2 => n => charRange(c1, c2).map(elemValue(n));
const varRangeExpanded = x.replace(rangeRegex, (_, c1, n1, c2, n2) =>
rangeFromString(n1, n2).map(addChars(c1)(c2))
);
const varRegex = /[A-J][1-9][0-9]?/gi;
const varExpanded = varRangeExpanded.replace(
varRegex,
match => document.getElementById(match.toUpperCase()).value
);
const functionExpanded = applyFn(varExpanded);
return functionExpanded === x
? functionExpanded
: evalFormula(functionExpanded);
};
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(x => {
createLabel(x);
letters.forEach(y => {
const input = document.createElement("input");
});
});
};
</script>
```
</div>
### Before Test
<div id='html-setup'>
```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Spreadsheet</title>
<style>
#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;
}
</style>
</head>
<body>
<div id="container">
<div></div>
</div>
```
</div>
### After Test
<div id='html-teardown'>
```html
</body>
</html>
```
</div>
</section>
## Solution
<section id='solution'>
```html
<script>
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, (_, arg1, fn, arg2) =>
infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
);
const highPrecedence = str => {
const regex = /([0-9.]+)([*\/])([0-9.]+)/;
const str2 = infixEval(str, regex);
return str === str2 ? str : highPrecedence(str2);
};
const spreadsheetFunctions = {
"": x => x
};
const applyFn = str => {
const noHigh = highPrecedence(str);
const infix = /([0-9.]+)([+-])([0-9.]+)/;
const str2 = infixEval(noHigh, infix);
const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
const toNumberList = args => args.split(",").map(parseFloat);
const applyFunction = (fn, args) =>
spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
return str2.replace(
regex,
(match, fn, args) =>
spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()) ? applyFunction(fn, args) : match
);
};
const range = (start, end) =>
start > end ? [] : [start].concat(range(start + 1, end));
const charRange = (start, end) =>
range(start.charCodeAt(0), end.charCodeAt(0)).map(x =>
String.fromCharCode(x)
);
const evalFormula = x => {
const rangeRegex = /([A-J])([1-9][0-9]?):([A-J])([1-9][0-9]?)/gi;
const rangeFromString = (n1, n2) => range(parseInt(n1), parseInt(n2));
const elemValue = n => c => document.getElementById(c + n).value;
const addChars = c1 => c2 => n => charRange(c1, c2).map(elemValue(n));
const varRangeExpanded = x.replace(rangeRegex, (_, c1, n1, c2, n2) =>
rangeFromString(n1, n2).map(addChars(c1)(c2))
);
const varRegex = /[A-J][1-9][0-9]?/gi;
const varExpanded = varRangeExpanded.replace(
varRegex,
match => document.getElementById(match.toUpperCase()).value
);
const functionExpanded = applyFn(varExpanded);
return functionExpanded === x
? functionExpanded
: evalFormula(functionExpanded);
};
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(x => {
createLabel(x);
letters.forEach(y => {
const input = document.createElement("input");
input.type = "text";
input.id = y + x;
input.onchange = update;
container.appendChild(input);
});
});
};
</script>
```
</section>