When should you use return statement in ES6 arrow functions?

Question

The new ES6 arrow functions say that in some cases, return is implicit:

This expression is also the implicit return value of the function.

In what situations do I need to use return in an ES6 arrow function?

Answer 1

I understand this rule of thumb...

The candidates are:

// 平方根
value => Math.sqrt(value)

// 求和
(a,b) => a+b

For other operations (if multiple lines of code are required, an explicit return value is required)

Answer 2

Jackson partially answered this question in a similar question:

I would like to add the definition of block:

Example:

// 返回：undefined
// 解释：一个空的带有隐式返回的块
((name) => {})() 

// 返回：'Hi Jess'
// 解释：没有块意味着隐式返回
((name) => 'Hi ' + name)('Jess')

// 返回：undefined
// 解释：块内需要显式返回，但是缺少了
((name) => {'Hi ' + name})('Jess')

// 返回：'Hi Jess'
// 解释：块内有显式返回
((name) => {return 'Hi ' + name})('Jess') 

// 返回：undefined
// 解释：一个包含单个标签的块。没有显式返回。
// 更多信息：https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/label
((name) => {id: name})('Jess') 

// 返回：{id: 'Jess'}
// 解释：隐式返回表达式 ( )，其求值为一个对象
((name) => ({id: name}))('Jess') 

// 返回：{id: 'Jess'}
// 解释：块内有显式返回对象
((name) => {return {id: name}})('Jess')