組織/組基於條件的陣列 - 的JavaScript

Question

如何可以簡化陣列

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

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

Answer 1

迭代通過數組元素

1. 提取國家和城市分別
2. 更新國家城市地圖（您的對象可以跟蹤映射到哪個城市的國家）
3. 通過此對象的鍵，並與您的國家城市創建一個新的陣列。如果該國家有城市陣列，請使用join(',')獲取逗號分隔的城市字符串。

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);