87 lines
2.1 KiB
Markdown
87 lines
2.1 KiB
Markdown
---
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id: 587d7b8d367417b2b2512b5b
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title: Learn About Functional Programming
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challengeType: 1
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forumTopicId: 301233
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dashedName: learn-about-functional-programming
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---
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# --description--
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Functional programming is a style of programming where solutions are simple, isolated functions, without any side effects outside of the function scope: `INPUT -> PROCESS -> OUTPUT`
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Functional programming is about:
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1) Isolated functions - there is no dependence on the state of the program, which includes global variables that are subject to change
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2) Pure functions - the same input always gives the same output
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3) Functions with limited side effects - any changes, or mutations, to the state of the program outside the function are carefully controlled
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# --instructions--
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The members of freeCodeCamp happen to love tea.
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In the code editor, the `prepareTea` and `getTea` functions are already defined for you. Call the `getTea` function to get 40 cups of tea for the team, and store them in the `tea4TeamFCC` variable.
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# --hints--
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The `tea4TeamFCC` variable should hold 40 cups of tea for the team.
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```js
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assert(tea4TeamFCC.length === 40);
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```
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The `tea4TeamFCC` variable should hold cups of green tea.
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```js
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assert(tea4TeamFCC[0] === 'greenTea');
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```
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# --seed--
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## --seed-contents--
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```js
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// Function that returns a string representing a cup of green tea
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const prepareTea = () => 'greenTea';
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/*
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Given a function (representing the tea type) and number of cups needed, the
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following function returns an array of strings (each representing a cup of
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a specific type of tea).
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*/
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const getTea = (numOfCups) => {
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const teaCups = [];
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for(let cups = 1; cups <= numOfCups; cups += 1) {
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const teaCup = prepareTea();
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teaCups.push(teaCup);
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}
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return teaCups;
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};
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// Only change code below this line
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const tea4TeamFCC = null;
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// Only change code above this line
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```
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# --solutions--
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```js
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const prepareTea = () => 'greenTea';
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const getTea = (numOfCups) => {
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const teaCups = [];
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for(let cups = 1; cups <= numOfCups; cups += 1) {
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const teaCup = prepareTea();
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teaCups.push(teaCup);
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}
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return teaCups;
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};
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const tea4TeamFCC = getTea(40);
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```
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