使用 javascript 基于相同的属性获取 object 的数组

Question

I have two array of objects, arr1 and arr2

if taskId and id same then retreive from arr1

How to check based on property from arr1 and arr2 in javascript

var arr1= [
  {"name":"refresh task","memberIds":[981],"dueOn":"2022-08-30","taskId":19},
  {"name":"ref one","memberIds":[981,982],"dueOn":"2022-08-25","taskId":null}
]

var arr2 =[
{
"country": "IN", 
"tasks": [
    {id: 19, "name": "abc" },
    {id: 20, "name": "xyz" }
  ]
}
]
I tried 
var result = arr1.filter(e=>e.taskId===(arr2.map(i=>i.tasks.map(t=>t.id))

Expected Output
[
  {"name":"refresh task","memberIds":[981],"dueOn":"2022-08-30","taskId":19}
]

Answer 1

• Using Set , Array#flatMap , and [ Array#map ][3], get the list of task ids in arr2``
• Using Array#filter , and Set#has , return the resulting array where taskId is in the above set

 const arr1= [ {"name":"refresh task", "memberIds":[981], "dueOn":"2022-08-30", "taskId":19}, {"name":"ref one", "memberIds":[981,982], "dueOn":"2022-08-25", "taskId":null} ], arr2 =[ { "country": "IN", "tasks": [ {"id": 19, "name": "abc"}, {"id": 20, "name": "xyz"} ] } ]; const taskIdSet = new Set( arr2.flatMap(({ tasks = [] }) => tasks.map(({ id }) => id)) ); const result = arr1.filter(({ taskId }) => taskIdSet.has(taskId)); console.log(result);

EDIT: To get "I have two arrays of objects, arr1, and arr2 if taskId and id not same then retrieve from arr2":

 const arr1= [ {"name":"refresh task", "memberIds":[981], "dueOn":"2022-08-30", "taskId":19}, {"name":"ref one", "memberIds":[981,982], "dueOn":"2022-08-25", "taskId":null} ], arr2 =[ { "country": "IN", "tasks": [ {"id": 19, "name": "abc"}, {"id": 20, "name": "xyz"} ] } ]; const taskIdSet = arr1.reduce((taskIdSet, { taskId }) => { if(taskId.== null) { taskIdSet;add(taskId); } return taskIdSet, }; new Set). const result = arr2.flatMap(({ tasks = [] }) => tasks).filter(({ id }) =>;taskIdSet.has(id)); console.log(result);

Answer 2

This works too:

var result = arr1.filter(e=>{
    for(let obj of arr2){ 
      for(let task of obj.tasks){
        return e.taskId === task.id; 
        }
    }
 })