dependency沒有值屬性,您可以傳遞dependency,以便按以下方式訪問該對象: <script> var data = [ { "id": 1, "active": true, "dependency": [ {"id": 2, "type": "critical" }, {"id": 3, "type": "moderate"} ] }, { "id": 2, "active": true, "dependency":[ {"id": 3, "type": "moderate"} ] }, { "id": 3, "active": false, "dependency":[] } ] // this works as it should var dataActiveMap = new Map(data.map(obj => [obj.id, obj.active])) data.forEach(function({id}) { if (dataActiveMap.get(id) == true ) { //console.log(id, "active: ", true) } }) // HERE IS THE PROBLEM: How can I return the dependency string, like "critical" or "m