javascript - 根据其他数组的内容创建一个对象数组 "complete"

Question

我有 3 个数组:

var countries = ['Montenegro', 'Spain', 'Belgium']
var years = ['2000', '2001', '2002', '2003'];
var death = ['cancer', 'measles'];

和一个对象数组:

var values = [
    {country:'Montenegro', year:'2000', death:'cancer', number:'50'},
    {country:'Montenegro', year:'2001', death:'cancer', number:'60'},
    {country:'Montenegro', year:'2002', death:'cancer', number:'70'},
    {country:'Montenegro', year:'2003', death:'cancer', number:'80'},
    {country:'Spain', year:'2000', death:'cancer', number:'NaN'},
    {country:'Spain', year:'2001', death:'cancer', number:'110'},
    {country:'Spain', year:'2002', death:'cancer', number:'120'},
    {country:'Spain', year:'2003', death:'cancer', number:'130'},
    {country:'Belgium', year:'2000', death:'cancer', number:'70'},
    {country:'Belgium', year:'2001', death:'cancer', number:'80'},
    {country:'Belgium', year:'2002', death:'cancer', number:'90.5'},
    {country:'Montenegro', year:'2000', death:'measles', number:''},
    {country:'Montenegro', year:'2001', death:'measles', number:'1'},
    {country:'Montenegro', year:'2002', death:'measles', number:'2'},
    {country:'Montenegro', year:'2003', death:'measles', number:'3'},
    {country:'Spain', year:'2000', death:'measles', number:'2'},
    {country:'Spain', year:'2001', death:'measles', number:'3'},
    {country:'Spain', year:'2002', death:'measles', number:'NaN'},
    {country:'Spain', year:'2003', death:'measles', number:'5'}
];

我想要的是一个“完整”的对象数组，其中包含三个数组中存在的所有可能的值组合。

values 事实上，不包含与以下内容相关的对象:

{country:'Belgium', year:'2003', death:'cancer', ...},
{country:'Belgium', year:'2000', death:'measles', ...},
{country:'Belgium', year:'2001', death:'measles', ...},
{country:'Belgium', year:'2002', death:'measles', ...},
{country:'Belgium', year:'2003', death:'measles', ...}

所以我想得到这个新对象(缺失的数据设置为NaN):

var valuesComplete = [
    {country:'Montenegro', year:'2000', death:'cancer', number:'50'},
    {country:'Montenegro', year:'2001', death:'cancer', number:'60'},
    {country:'Montenegro', year:'2002', death:'cancer', number:'70'},
    {country:'Montenegro', year:'2003', death:'cancer', number:'80'},
    {country:'Spain', year:'2000', death:'cancer', number:'NaN'},
    {country:'Spain', year:'2001', death:'cancer', number:'110'},
    {country:'Spain', year:'2002', death:'cancer', number:'120'},
    {country:'Spain', year:'2003', death:'cancer', number:'130'},
    {country:'Belgium', year:'2000', death:'cancer', number:'70'},
    {country:'Belgium', year:'2001', death:'cancer', number:'80'},
    {country:'Belgium', year:'2002', death:'cancer', number:'90.5'},
    {country:'Belgium', year:'2003', death:'cancer', number:NaN}, // <--
    {country:'Montenegro', year:'2000', death:'measles', number:''},
    {country:'Montenegro', year:'2001', death:'measles', number:'1'},
    {country:'Montenegro', year:'2002', death:'measles', number:'2'},
    {country:'Montenegro', year:'2003', death:'measles', number:'3'},
    {country:'Spain', year:'2000', death:'measles', number:'2'},
    {country:'Spain', year:'2001', death:'measles', number:'3'},
    {country:'Spain', year:'2002', death:'measles', number:'NaN'},
    {country:'Spain', year:'2003', death:'measles', number:'5'},
    {country:'Belgium', year:'2000', death:'measles', number:NaN}, // <--
    {country:'Belgium', year:'2001', death:'measles', number:NaN}, // <--
    {country:'Belgium', year:'2002', death:'measles', number:NaN}, // <--
    {country:'Belgium', year:'2003', death:'measles', number:NaN} // <--
];

新数组包含 24 个元素 = countries.length *years.length *death.length。

最好的方法是什么？

Answer 1

您可以检查所有可能的组合。使用map循环遍历每个数组并使用find搜索它

var countries = ['Montenegro', 'Spain', 'Belgium']
var years = ['2000', '2001', '2002', '2003'];
var death = ['cancer', 'measles'];

var values = [
   {country:'Montenegro', year:'2000', death:'cancer', number:'50'},
   {country:'Montenegro', year:'2001', death:'cancer', number:'60'},
   {country:'Montenegro', year:'2002', death:'cancer', number:'70'},
   {country:'Montenegro', year:'2003', death:'cancer', number:'80'},
   {country:'Spain', year:'2000', death:'cancer', number:'NaN'},
   {country:'Spain', year:'2001', death:'cancer', number:'110'},
   {country:'Spain', year:'2002', death:'cancer', number:'120'},
   {country:'Spain', year:'2003', death:'cancer', number:'130'},
   {country:'Belgium', year:'2000', death:'cancer', number:'70'},
   {country:'Belgium', year:'2001', death:'cancer', number:'80'},
   {country:'Belgium', year:'2002', death:'cancer', number:'90.5'},
   {country:'Montenegro', year:'2000', death:'measles', number:''},
   {country:'Montenegro', year:'2001', death:'measles', number:'1'},
   {country:'Montenegro', year:'2002', death:'measles', number:'2'},
   {country:'Montenegro', year:'2003', death:'measles', number:'3'},
   {country:'Spain', year:'2000', death:'measles', number:'2'},
   {country:'Spain', year:'2001', death:'measles', number:'3'},
   {country:'Spain', year:'2002', death:'measles', number:'NaN'},
   {country:'Spain', year:'2003', death:'measles', number:'5'}
];

var valuesComplete = [countries, years, death].reduce((c, v) => [].concat(...c.map(o => v.map(x => [].concat(o, x)))))
                     .map(o => values.find(v => v.country === o[0] && v.year === o[1] && v.death === o[2]) || {country: o[0],year: o[1],death: o[2],number: NaN})

console.log(valuesComplete);