從 Javascript 中的嵌套數組 object 中創建扁平值數組

Question

我有以下數組 object。

    let reports = [
        {
            cc: 'BEL',
            cn: 'Belgium',
            entities: [
                {
                    entityName: 'Company A',
                    address: 'some address'
                }, 
                {
                    entityName: 'Company B',
                    address: 'some address'
                }
            ]
        },
        {
            cc: 'LUX',
            cn: 'Luxembourg',
            entities: [
                {
                    entityName: 'Company C',
                    address: 'some address'
                }
            ]
        }
    ];

我想通過reports go 並創建一個只有entityName值的新數組，我該如何實現？

新數組應類似於['Company A', 'Company B', 'Company C'] 。 我怎樣才能做到這一點？

我嘗試這樣做： reports.map(e => e.entities.map(r => r.entityName)) 。 然而，這返回：

[['Company A', 'Company B'], ['Company C']]

Answer 1

您可以對結果使用.flat() 。

 let reports = [ { cc: 'BEL', cn: 'Belgium', entities: [ { entityName: 'Company A', address: 'some address' }, { entityName: 'Company B', address: 'some address' } ] }, { cc: 'LUX', cn: 'Luxembourg', entities: [ { entityName: 'Company C', address: 'some address' } ] } ]; const res = reports.map(e => e.entities.map(r => r.entityName)).flat(); console.log(res);

Answer 2

我會這樣做，首先是 map 個實體，然后將它們扁平化，最后將 entityNames 作為單個數組結果返回：

 let reports = [{ cc: 'BEL', cn: 'Belgium', entities: [{ entityName: 'Company A', address: 'some address' }, { entityName: 'Company B', address: 'some address' } ] }, { cc: 'LUX', cn: 'Luxembourg', entities: [{ entityName: 'Company C', address: 'some address' }] } ]; const flattenedEntities = reports.map(({entities}) => entities).flat().map(({entityName}) => entityName); console.log(flattenedEntities);

Answer 3

您可以簡單地通過使用for循環來獲得。

 var reports = [ { cc: 'BEL', cn: 'Belgium', entities: [ { entityName: 'Company A', address: 'some address' }, { entityName: 'Company B', address: 'some address' } ] }, { cc: 'LUX', cn: 'Luxembourg', entities: [ { entityName: 'Company C', address: 'some address' } ] } ]; var yourarray = []; for (var j = 0; j < reports.length; j++) { var reportentity = reports[j].entities; for (var i = 0; i < reportentity.length; i++) { yourarray.push(reportentity[i].entityName); } } console.log(yourarray)