根据条件组织/分组数组 - javascript

Question

如何简化数组

[ china, country1(city1), country1(city2), country1(city3)), korea, australia]到

[ china, country1(city1, city2, city3), korea, australia]

Answer 1

遍历数组元素

1. 分别提取国家和城市
2. 更新国家/地区城市地图（跟踪映射到哪些城市的国家/地区的对象）
3. 浏览此对象的键并使用您的国家/地区城市创建一个新阵列。如果该国家/地区有城市数组，请使用join(',')获取以逗号分隔的城市字符串。

var cityRegex = /\((.*)\)/;
var countryRegex = /([^()]*)\(?.*\)?/;

var countryCityArray = ['china', 'country1(city1)', 'country1(city2)', 'country1(city3)', 'korea', 'australia'];

var countryCityMap = {};

countryCityArray.forEach(function(countryCity) {
  var matches = countryRegex.exec(countryCity);
  var country = matches[1]
  if (!countryCityMap[country]) {
    countryCityMap[country] = [];
  }

  matches = cityRegex.exec(countryCity);

  if (matches && matches.length) {
    var city = matches[1];
    countryCityMap[country].push(city);
  }

});

var targetArray = Object.keys(countryCityMap).map(function(country) {
  var countryCity = country;
  if (countryCityMap[country].length) {
    countryCity = countryCity + '(' + countryCityMap[country].join(',') + ')';
  }
  return countryCity;
});

console.log(targetArray);