Format a string of names like 'Bart, Lisa & Maggie'.

链接： https://www.codewars.com/kata/format-a-string-of-names-like-bart-lisa-and-maggie

题目介绍

Given: an array containing hashes of names

Return: a string formatted as a list of names separated by commas except for the last two names, which should be separated by an ampersand.

Example:

list([ {name: 'Bart'}, {name: 'Lisa'}, {name: 'Maggie'} ])
// returns 'Bart, Lisa & Maggie'

list([ {name: 'Bart'}, {name: 'Lisa'} ])
// returns 'Bart & Lisa'

list([ {name: 'Bart'} ])
// returns 'Bart'

list([])
// returns ''

Note: all the hashes are pre-validated and will only contain A-Z, a-z, '-' and '.'.

解题思路

我看到题目第一反应用正则。

• 第一步 names.map(x=>x.name)，遍历得到数组： ['Bart', 'Lisa', 'Maggie']
• 逗号分隔 .join(', ') 得到字符串：'Bart, Lisa, Maggie'
• 正则替换最后一个 ', ' 为 ' & '

参考答案

一句话代码解决方案，我的提交：

const list = names =>
  names.map(x=>x.name)
    .join(', ')
    .replace(/,\s(\w+)$/,' & $1');

拓展阅读

《边学边玩酷JS》

• 正则表达式章节： https://learn.js.cool/regexp/base.html
• 数组章节： https://learn.js.cool/base/array.html