2018-09-30 23:01:58 +01:00
|
|
|
---
|
|
|
|
id: 587d7b8b367417b2b2512b50
|
|
|
|
title: Write Concise Declarative Functions with ES6
|
|
|
|
challengeType: 1
|
2019-08-05 09:17:33 -07:00
|
|
|
forumTopicId: 301224
|
2021-01-13 03:31:00 +01:00
|
|
|
dashedName: write-concise-declarative-functions-with-es6
|
2018-09-30 23:01:58 +01:00
|
|
|
---
|
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
# --description--
|
|
|
|
|
|
|
|
When defining functions within objects in ES5, we have to use the keyword `function` as follows:
|
2019-05-17 06:20:30 -07:00
|
|
|
|
|
|
|
```js
|
|
|
|
const person = {
|
|
|
|
name: "Taylor",
|
|
|
|
sayHello: function() {
|
|
|
|
return `Hello! My name is ${this.name}.`;
|
|
|
|
}
|
|
|
|
};
|
|
|
|
```
|
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
With ES6, You can remove the `function` keyword and colon altogether when defining functions in objects. Here's an example of this syntax:
|
2019-05-17 06:20:30 -07:00
|
|
|
|
|
|
|
```js
|
|
|
|
const person = {
|
|
|
|
name: "Taylor",
|
|
|
|
sayHello() {
|
|
|
|
return `Hello! My name is ${this.name}.`;
|
|
|
|
}
|
|
|
|
};
|
|
|
|
```
|
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
# --instructions--
|
|
|
|
|
|
|
|
Refactor the function `setGear` inside the object `bicycle` to use the shorthand syntax described above.
|
|
|
|
|
|
|
|
# --hints--
|
2018-09-30 23:01:58 +01:00
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
Traditional function expression should not be used.
|
2018-09-30 23:01:58 +01:00
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
```js
|
|
|
|
(getUserInput) => assert(!__helpers.removeJSComments(code).match(/function/));
|
|
|
|
```
|
2018-09-30 23:01:58 +01:00
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
`setGear` should be a declarative function.
|
2018-09-30 23:01:58 +01:00
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
```js
|
|
|
|
assert(
|
|
|
|
typeof bicycle.setGear === 'function' && code.match(/setGear\s*\(.+\)\s*\{/)
|
|
|
|
);
|
2018-09-30 23:01:58 +01:00
|
|
|
```
|
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
`bicycle.setGear(48)` should change the `gear` value to 48.
|
2018-09-30 23:01:58 +01:00
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
```js
|
|
|
|
assert(new bicycle.setGear(48).gear === 48);
|
|
|
|
```
|
|
|
|
|
|
|
|
# --seed--
|
2018-09-30 23:01:58 +01:00
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
## --seed-contents--
|
2018-09-30 23:01:58 +01:00
|
|
|
|
|
|
|
```js
|
2020-03-04 13:08:54 -06:00
|
|
|
// Only change code below this line
|
2018-09-30 23:01:58 +01:00
|
|
|
const bicycle = {
|
|
|
|
gear: 2,
|
|
|
|
setGear: function(newGear) {
|
|
|
|
this.gear = newGear;
|
|
|
|
}
|
|
|
|
};
|
2020-03-04 13:08:54 -06:00
|
|
|
// Only change code above this line
|
2018-09-30 23:01:58 +01:00
|
|
|
bicycle.setGear(3);
|
|
|
|
console.log(bicycle.gear);
|
|
|
|
```
|
|
|
|
|
2020-11-27 19:02:05 +01:00
|
|
|
# --solutions--
|
2018-09-30 23:01:58 +01:00
|
|
|
|
|
|
|
```js
|
2019-02-13 22:11:56 +03:00
|
|
|
const bicycle = {
|
|
|
|
gear: 2,
|
|
|
|
setGear(newGear) {
|
|
|
|
this.gear = newGear;
|
|
|
|
}
|
|
|
|
};
|
|
|
|
bicycle.setGear(3);
|
2018-09-30 23:01:58 +01:00
|
|
|
```
|