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Co-authored-by: Jessica Wilkins <67210629+jdwilkin4@users.noreply.github.com> Co-authored-by: Krzysztof G. <60067306+gikf@users.noreply.github.com>
165 lines
4.0 KiB
Markdown
165 lines
4.0 KiB
Markdown
---
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id: 646d3d65be79c8bb9c7df9ff
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title: Step 66
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challengeType: 0
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dashedName: step-66
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---
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# --description--
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Now create a `-` property that is a function that takes an `x` and `y` parameter and implicitly returns the result of subtracting `y` from `x`.
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# --hints--
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Your `infixToFunction` object should have a `-` property.
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```js
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assert.property(infixToFunction, '-');
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```
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Your `-` property should be a function.
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```js
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assert.isFunction(infixToFunction['-']);
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```
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Your `-` function should use arrow syntax.
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```js
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assert.match(code, /('|"|`)-\1\s*:\s*\(/);
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```
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Your `-` function should have `x` as its first parameter.
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```js
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assert.match(code, /('|"|`)-\1\s*:\s*\(\s*x/);
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```
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Your `-` function should have `y` as its second parameter.
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```js
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assert.match(code, /('|"|`)-\1\s*:\s*\(\s*x\s*,\s*y\s*\)/);
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```
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Your `-` function should use an implicit return.
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```js
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assert.notMatch(code, /('|"|`)-\1\s*:\s*\(\s*x\s*,\s*y\s*\)\s*\{/);
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```
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Your `-` function should return the result of subtracting `y` from `x`.
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```js
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assert.equal(infixToFunction['-'](1, 2), -1);
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```
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# --seed--
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## --seed-contents--
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```html
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="utf-8" />
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<meta name="viewport" content="width=device-width, initial-scale=1" />
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<link rel="stylesheet" href="./styles.css" />
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<title>Functional Programming Spreadsheet</title>
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</head>
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<body>
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<div id="container">
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<div></div>
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</div>
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<script src="./script.js"></script>
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</body>
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</html>
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```
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```css
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#container {
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display: grid;
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grid-template-columns: 50px repeat(10, 200px);
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grid-template-rows: repeat(11, 30px);
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}
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.label {
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background-color: lightgray;
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text-align: center;
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vertical-align: middle;
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line-height: 30px;
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}
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```
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```js
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--fcc-editable-region--
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const infixToFunction = {
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"+": (x, y) => x + y,
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}
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--fcc-editable-region--
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const isEven = num => num % 2 === 0;
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const sum = nums => nums.reduce((acc, el) => acc + el, 0);
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const average = nums => sum(nums) / nums.length;
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const median = nums => {
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const sorted = nums.slice().sort((a, b) => a - b);
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const length = sorted.length;
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const middle = length / 2 - 1;
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return isEven(length)
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? average([sorted[middle], sorted[middle + 1]])
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: sorted[Math.ceil(middle)];
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}
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const spreadsheetFunctions = {
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sum,
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average,
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median
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}
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const range = (start, end) => Array(end - start + 1).fill(start).map((element, index) => element + index);
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const charRange = (start, end) => range(start.charCodeAt(0), end.charCodeAt(0)).map(code => String.fromCharCode(code));
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const evalFormula = (x, cells) => {
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const idToText = id => cells.find(cell => cell.id === id).value;
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const rangeRegex = /([A-J])([1-9][0-9]?):([A-J])([1-9][0-9]?)/gi;
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const rangeFromString = (num1, num2) => range(parseInt(num1), parseInt(num2));
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const elemValue = num => character => idToText(character + num);
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const addCharacters = character1 => character2 => num => charRange(character1, character2).map(elemValue(num));
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const rangeExpanded = x.replace(rangeRegex, (_match, char1, num1, char2, num2) => rangeFromString(num1, num2).map(addCharacters(char1)(char2)));
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const cellRegex = /[A-J][1-9][0-9]?/gi;
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const cellExpanded = rangeExpanded.replace(cellRegex, match => idToText(match.toUpperCase()));
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}
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window.onload = () => {
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const container = document.getElementById("container");
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const createLabel = (name) => {
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const label = document.createElement("div");
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label.className = "label";
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label.textContent = name;
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container.appendChild(label);
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}
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const letters = charRange("A", "J");
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letters.forEach(createLabel);
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range(1, 99).forEach(number => {
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createLabel(number);
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letters.forEach(letter => {
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const input = document.createElement("input");
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input.type = "text";
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input.id = letter + number;
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input.ariaLabel = letter + number;
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input.onchange = update;
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container.appendChild(input);
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})
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})
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}
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const update = event => {
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const element = event.target;
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const value = element.value.replace(/\s/g, "");
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if (!value.includes(element.id) && value.startsWith('=')) {
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}
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}
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```
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