120 lines
4.2 KiB
Markdown
120 lines
4.2 KiB
Markdown
---
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id: 587d7b8a367417b2b2512b4e
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title: Create Strings using Template Literals
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challengeType: 1
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---
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## Description
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<section id='description'>
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A new feature of ES6 is the <dfn>template literal</dfn>. This is a special type of string that makes creating complex strings easier.
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Template literals allow you to create multi-line strings and to use string interpolation features to create strings.
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Consider the code below:
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```js
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const person = {
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name: "Zodiac Hasbro",
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age: 56
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};
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// Template literal with multi-line and string interpolation
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const greeting = `Hello, my name is ${person.name}!
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I am ${person.age} years old.`;
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console.log(greeting); // prints
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// Hello, my name is Zodiac Hasbro!
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// I am 56 years old.
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```
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A lot of things happened there.
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Firstly, the example uses backticks (<code>`</code>), not quotes (<code>'</code> or <code>"</code>), to wrap the string.
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Secondly, notice that the string is multi-line, both in the code and the output. This saves inserting <code>\n</code> within strings.
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The <code>${variable}</code> syntax used above is a placeholder. Basically, you won't have to use concatenation with the <code>+</code> operator anymore. To add variables to strings, you just drop the variable in a template string and wrap it with <code>${</code> and <code>}</code>. Similarly, you can include other expressions in your string literal, for example <code>${a + b}</code>.
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This new way of creating strings gives you more flexibility to create robust strings.
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</section>
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## Instructions
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<section id='instructions'>
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Use template literal syntax with backticks to display each entry of the <code>result</code> object's <code>failure</code> array. Each entry should be wrapped inside an <code>li</code> element with the class attribute <code>text-warning</code>, and listed within the <code>resultDisplayArray</code>.
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Use an iterator method (any kind of loop) to get the desired output.
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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: <code>resultDisplayArray</code> is an array containing <code>result failure</code> messages.
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testString: assert(typeof makeList(result.failure) === 'object' && resultDisplayArray.length === 3, '<code>resultDisplayArray</code> is a list containing <code>result failure</code> messages.');
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- text: <code>resultDisplayArray</code> is the desired output.
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testString: assert(makeList(result.failure).every((v, i) => v === `<li class="text-warning">${result.failure[i]}</li>` || v === `<li class='text-warning'>${result.failure[i]}</li>`), '<code>resultDisplayArray</code> is the desired output.');
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- text: Template strings and expression interpolation should be used
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testString: getUserInput => assert(getUserInput('index').match(/(`.*\${.*}.*`)/), 'Template strings and expression interpolation should be used');
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- text: An iterator should be used
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testString: getUserInput => assert(getUserInput('index').match(/for|map|reduce|forEach|while/), 'An iterator should be used');
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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='js-seed'>
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```js
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const result = {
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success: ["max-length", "no-amd", "prefer-arrow-functions"],
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failure: ["no-var", "var-on-top", "linebreak"],
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skipped: ["id-blacklist", "no-dup-keys"]
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};
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function makeList(arr) {
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"use strict";
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// change code below this line
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const resultDisplayArray = null;
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// change code above this line
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return resultDisplayArray;
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}
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/**
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* makeList(result.failure) should return:
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* [ `<li class="text-warning">no-var</li>`,
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* `<li class="text-warning">var-on-top</li>`,
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* `<li class="text-warning">linebreak</li>` ]
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**/
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const resultDisplayArray = makeList(result.failure);
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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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```js
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const result = {
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success: ["max-length", "no-amd", "prefer-arrow-functions"],
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failure: ["no-var", "var-on-top", "linebreak"],
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skipped: ["id-blacklist", "no-dup-keys"]
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};
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function makeList(arr) {
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"use strict";
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const resultDisplayArray = arr.map(val => `<li class="text-warning">${val}</li>`);
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return resultDisplayArray;
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}
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/**
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* makeList(result.failure) should return:
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* [ `<li class="text-warning">no-var</li>`,
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* `<li class="text-warning">var-on-top</li>`,
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* `<li class="text-warning">linebreak</li>` ]
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**/
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const resultDisplayArray = makeList(result.failure);
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```
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</section>
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