How do i map through array to get array of object?

Question

I have an array called data. How do i extract sub_data? Just need the sub_data part for each object.

const data = [
  {
    id: 1,
    title: 'Logo'
    sub_data: [
      {
        id: 2,
        title: 'Company Logo'
      },
      {
        id: 3,
        title: 'Website Logo'
      }, 
    ]
  },
  {
    id: 2,
    title: 'Brands'
    sub_data: [
      {
        id: 25,
        title: 'Company Brands'
      },
      {
        id: 3,
        title: 'Website Brands'
      }, 
    ]
  }
]

Example output will get two outputs because there is 2 objects:

const subData = [
      {
        id: 2,
        title: 'Company Logo'
      },
      {
        id: 3,
        title: 'Website Logo'
      }, 
]


const subData = [
       {
        id: 25,
        title: 'Company Brands'
      },
      {
        id: 3,
        title: 'Website Brands'
      },  
]

Not very sure how to use the map function just to get sub_data in the correct structure

@RobertoZvjerković I'd use ?.sub_data in case of not found. — Hao Wu
– Hao Wu, Commented Jul 13, 2022 at 8:08
You can't have 2 outputs from one operation. By 2 outputs do you mean a nested array that contains your desired arrays? — Hao Wu
– Hao Wu, Commented Jul 13, 2022 at 8:13

Nick Vu · Accepted Answer · 2022-07-13 08:11:06Z

2

You can use flatMap to get sub_data in one array

const data = [
  {
    id: 1,
    title: 'Logo',
    sub_data: [
      {
        id: 2,
        title: 'Company Logo'
      },
      {
        id: 3,
        title: 'Website Logo'
      }, 
    ]
  },
  {
    id: 2,
    title: 'Brands',
    sub_data: [
      {
        id: 25,
        title: 'Company Brands'
      },
      {
        id: 3,
        title: 'Website Brands'
      }, 
    ]
  }
]

const result = data.flatMap(item => item.sub_data)

console.log(result)

answered Jul 13, 2022 at 8:11

Nick Vu

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2 Comments

Toni Bardina Comas Over a year ago

I haven't been fast enough haha

Nick Vu Over a year ago

haha, you and I have the same thought though. :D

Toni Bardina Comas · Accepted Answer · 2022-07-13 08:09:56Z

1

If you want an array with the sub_data objects you can just map the original array:

const data = [
  {
    id: 1,
    title: 'Logo',
    'sub_data'
    : [
      {
        id: 2,
        title: 'Company Logo'
      },
      {
        id: 3,
        title: 'Website Logo'
      }, 
    ]
  },
  {
    id: 2,
    title: 'Brands',
    sub_data: [
      {
        id: 25,
        title: 'Company Brands'
      },
      {
        id: 3,
        title: 'Website Brands'
      }, 
    ]
  }
]

const mappedData = data.flatMap(obj => obj.sub_data)

console.log(mappedData)

answered Jul 13, 2022 at 8:09

Toni Bardina Comas

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Comments

Athii · Accepted Answer · 2022-07-13 08:12:25Z

1

Another solution would be to use the .forEach function of javascript.

const subData = [];
data.forEach(item => subData.push(...item.sub_data))

answered Jul 13, 2022 at 8:12

Athii

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