216 lines
4.6 KiB
Markdown
216 lines
4.6 KiB
Markdown
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---
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id: 5d792536735f71d746ee5d99
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title: Step 061
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challengeType: 0
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isBeta: true
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---
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## Description
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<section id='description'>
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You might think that this wouldn't work because `fn` wouldn't have access to `n` after `elemValue` has finished executing.
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However, this works because of closures - functions have access to all variables declared at their time of creation.
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Inside `elemValue`, remove the variable `fn` and its definition, and replace `return fn` with `return c => document.getElementById(c + n).value`.
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: See description above for instructions.
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testString: assert(code.replace(/\s/g, "").includes("constelemValue=n=>{returnc=>document.getElementById(c+n).value"));
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='html-seed'>
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```html
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<script>
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const infixToFunction = {
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"+": (x, y) => x + y,
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"-": (x, y) => x - y,
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"*": (x, y) => x * y,
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"/": (x, y) => x / y
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};
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const infixEval = (str, regex) =>
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str.replace(regex, (_, arg1, fn, arg2) =>
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infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
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);
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const highPrecedence = str => {
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const regex = /([0-9.]+)([*\/])([0-9.]+)/;
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const str2 = infixEval(str, regex);
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return str === str2 ? str : highPrecedence(str2);
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};
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const spreadsheetFunctions = {
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"": x => x
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};
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const applyFn = str => {
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const noHigh = highPrecedence(str);
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const infix = /([0-9.]+)([+-])([0-9.]+)/;
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const str2 = infixEval(noHigh, infix);
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const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
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const toNumberList = args => args.split(",").map(parseFloat);
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const applyFunction = (fn, args) =>
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spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
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return str2.replace(
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regex,
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(match, fn, args) =>
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spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()) ? applyFunction(fn, args) : match
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);
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};
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const range = (start, end) =>
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start > end ? [] : [start].concat(range(start + 1, end));
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const charRange = (start, end) =>
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range(start.charCodeAt(0), end.charCodeAt(0)).map(x =>
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String.fromCharCode(x)
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);
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const evalFormula = x => {
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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 = (n1, n2) => range(parseInt(n1), parseInt(n2));
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const elemValue = n => {
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const fn = c => document.getElementById(c + n).value;
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return fn;
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};
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const fn = elemValue("1");
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return fn("A");
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};
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</script>
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```
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</div>
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### Before Test
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<div id='html-setup'>
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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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<title>Spreadsheet</title>
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<style>
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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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</style>
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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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```
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</div>
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### After Test
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<div id='html-teardown'>
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```html
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</body>
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</html>
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```html
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<script>
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const infixToFunction = {
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"+": (x, y) => x + y,
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"-": (x, y) => x - y,
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"*": (x, y) => x * y,
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"/": (x, y) => x / y
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};
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const infixEval = (str, regex) =>
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str.replace(regex, (_, arg1, fn, arg2) =>
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infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
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);
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const highPrecedence = str => {
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const regex = /([0-9.]+)([*\/])([0-9.]+)/;
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const str2 = infixEval(str, regex);
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return str === str2 ? str : highPrecedence(str2);
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};
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const spreadsheetFunctions = {
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"": x => x
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};
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const applyFn = str => {
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const noHigh = highPrecedence(str);
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const infix = /([0-9.]+)([+-])([0-9.]+)/;
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const str2 = infixEval(noHigh, infix);
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const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
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const toNumberList = args => args.split(",").map(parseFloat);
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const applyFunction = (fn, args) =>
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spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
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return str2.replace(
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regex,
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(match, fn, args) =>
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spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()) ? applyFunction(fn, args) : match
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);
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};
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const range = (start, end) =>
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start > end ? [] : [start].concat(range(start + 1, end));
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const charRange = (start, end) =>
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range(start.charCodeAt(0), end.charCodeAt(0)).map(x =>
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String.fromCharCode(x)
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);
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const evalFormula = x => {
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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 = (n1, n2) => range(parseInt(n1), parseInt(n2));
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const elemValue = n => {
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return c => document.getElementById(c + n).value;
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};
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const fn = elemValue("1");
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return fn("A");
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};
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</script>
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```
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</section>
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