freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/es6/write-concise-declarative-functions-with-es6.md

---
id: 587d7b8b367417b2b2512b50
title: Write Concise Declarative Functions with ES6
challengeType: 1
forumTopicId: 301224
dashedName: write-concise-declarative-functions-with-es6
---

# --description--

When defining functions within objects in ES5, we have to use the keyword `function` as follows:

```js
const person = {
  name: "Taylor",
  sayHello: function() {
    return `Hello! My name is ${this.name}.`;
  }
};
```

With ES6, You can remove the `function` keyword and colon altogether when defining functions in objects. Here's an example of this syntax:

```js
const person = {
  name: "Taylor",
  sayHello() {
    return `Hello! My name is ${this.name}.`;
  }
};
```

# --instructions--

Refactor the function `setGear` inside the object `bicycle` to use the shorthand syntax described above.

# --hints--

Traditional function expression should not be used.

```js
(getUserInput) => assert(!__helpers.removeJSComments(code).match(/function/));
```

`setGear` should be a declarative function.

```js
assert(
  typeof bicycle.setGear === 'function' && code.match(/setGear\s*\(.+\)\s*\{/)
);
```

`bicycle.setGear(48)` should change the `gear` value to 48.

```js
assert(new bicycle.setGear(48).gear === 48);
```

# --seed--

## --seed-contents--

```js
// Only change code below this line
const bicycle = {
  gear: 2,
  setGear: function(newGear) {
    this.gear = newGear;
  }
};
// Only change code above this line
bicycle.setGear(3);
console.log(bicycle.gear);
```

# --solutions--

```js
const bicycle = {
  gear: 2,
  setGear(newGear) {
    this.gear = newGear;
  }
};
bicycle.setGear(3);
```