使用嵌套数组过滤对象数组

Question

so I am trying to set up a nested filter on an array of objects. The thing is that the filter is applied inside the object on a key that is another array of objects.

here is the code:

const items = [
  { name: "123", id: 1, value:  true, arr: [{ id: 1 }] },
  { name: "456", id: 2, value: false, arr: [{ id: 2 }] },
  { name: "456", id: 2, value: false, arr: [{ id: 3 }] },
  { name: "456", id: 2, value: false, arr: [{ id: 4 }] },
  { name: "456", id: 2, value: false, arr: [{ id: 5 }] },
  { name: "456", id: 2, value: false, arr: [{ id: 6 }] },
];

const newArray = items.filter((objects) => {
  objects.arr.filter((item) => {
    if (item.id === 2) {
      return objects;
    }
     
  });
});
console.log(newArray);

I 'm not sure where to put the return because in this situation i just get an empty array.

Answer 1

You need to check the nested array contains the wanted id and return the result to the filter method.

 const items = [{ name: "123", id: 1, value: true, arr: [{ id: 1 }] }, { name: "456", id: 2, value: false, arr: [{ id: 2 }] }, { name: "456", id: 2, value: false, arr: [{ id: 3 }] }, { name: "456", id: 2, value: false, arr: [{ id: 4 }] }, { name: "456", id: 2, value: false, arr: [{ id: 5 }] }, { name: "456", id: 2, value: false, arr: [{ id: 6 }] }], result = items.filter(({ arr }) => arr.some(({ id }) => id === 2)); console.log(result);

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Answer 2

Use Array#some to check if current arr has an element with id equal to 2:

 const items = [ { name: "123", id: 1, value: true, arr: [{ id: 1 }] }, { name: "456", id: 2, value: false, arr: [{ id: 2 }] }, { name: "456", id: 2, value: false, arr: [{ id: 3 }] }, { name: "456", id: 2, value: false, arr: [{ id: 4 }] }, { name: "456", id: 2, value: false, arr: [{ id: 5 }] }, { name: "456", id: 2, value: false, arr: [{ id: 6 }] } ]; const newArray = items.filter(({ arr = [] }) => arr.some(({ id }) => id === 2) ); console.log(newArray);

Answer 3

As you contains only one object in arr then you can access this object by using [0] index.

Working Demo:

 const items = [ { name: "123", id: 1, value: true, arr: [{ id: 1 }] }, { name: "456", id: 2, value: false, arr: [{ id: 2 }] }, { name: "456", id: 2, value: false, arr: [{ id: 3 }] }, { name: "456", id: 2, value: false, arr: [{ id: 4 }] }, { name: "456", id: 2, value: false, arr: [{ id: 5 }] }, { name: "456", id: 2, value: false, arr: [{ id: 6 }] }, ]; const newArray = items.filter((obj) => { if (obj.arr[0].id === 2) { return obj; } }); console.log(newArray);

I answered you as per the issue you are facing but if you have multiple objects in your arr then you can go ahead with Array.some() method as suggested by other answers.