2019-11-05 02:09:40 -01:00
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---
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id: 5d792533717672657b81aa69
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2020-08-25 02:19:45 -07:00
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title: Part 18
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2019-11-05 02:09:40 -01:00
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challengeType: 0
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---
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2020-11-27 19:02:05 +01:00
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# --description--
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2019-11-05 02:09:40 -01:00
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When defining an arrow function with a single argument, the parentheses can be omitted:
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```js
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const greeting = name => `Hello !`;
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```
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Define a function `highPrecedence` which takes a single argument `str` and returns it.
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2020-11-27 19:02:05 +01:00
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# --hints--
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2019-11-05 02:09:40 -01:00
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2020-11-27 19:02:05 +01:00
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See description above for instructions.
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2019-11-05 02:09:40 -01:00
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2020-11-27 19:02:05 +01:00
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```js
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assert(highPrecedence('a') === 'a');
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2019-11-05 02:09:40 -01:00
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```
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2020-11-27 19:02:05 +01:00
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# --seed--
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2019-11-05 02:09:40 -01:00
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2020-11-27 19:02:05 +01:00
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## --before-user-code--
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2019-11-05 02:09:40 -01:00
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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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2020-11-27 19:02:05 +01:00
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## --after-user-code--
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2019-11-05 02:09:40 -01:00
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```html
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</body>
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</html>
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```
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2020-11-27 19:02:05 +01:00
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## --seed-contents--
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2019-11-05 02:09:40 -01:00
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2020-11-27 19:02:05 +01:00
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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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2019-11-05 02:09:40 -01:00
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2020-11-27 19:02:05 +01:00
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</script>
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```
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2019-11-05 02:09:40 -01:00
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2020-11-27 19:02:05 +01:00
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# --solutions--
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2019-11-05 02:09:40 -01:00
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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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const highPrecedence = str => str;
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</script>
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```
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