Use lodash groupBy function to categorize objects in an array

Question

i have an array of products that each product has a category object. I need to organize by category and include the category object. GroupBy function include only one parameter.

the array of products

const data = [   
  {id: 1, 'name': 'produto1', category: {id: 1, name: 'shirts', description: 'super roupa'}},
  {id: 2, 'name': 'produto2', category: {id: 1, name: 'shirts', description: 'super roupa'}},
  {id: 3, 'name': 'produto3', category: {id: 2, name: 'jackets', description: 'super jackets'}},
  {id: 4, 'name': 'produto4', category: {id: 2, name: 'jackets', description: 'super jackets'}},    
]

expected result:

[
  {
    category: {id: 1, name: 'clothes', description: 'super roupa'}, 
    products:[{id:1, name: 'produt1'}, {id: 2, name: 'produto1'} ]
  },
  {
    category: {id: 2, name: 'jackets', description: 'super jackets'}, 
    products:[{id:3, name: 'produt3'}, {id: 4, name: 'produto4'} ]
  },
]

Answer 1

Group by the category.id, and then map the each group to an object by taking the category from the 1st item in the group, and omitting category from all products:

const data = [{"id":1,"name":"produto1","category":{"id":1,"name":"shirts","description":"super roupa"}},{"id":2,"name":"produto2","category":{"id":1,"name":"shirts","description":"super roupa"}},{"id":3,"name":"produto3","category":{"id":2,"name":"jackets","description":"super jackets"}},{"id":4,"name":"produto4","category":{"id":2,"name":"jackets","description":"super jackets"}}]

const result = _(data)
  .groupBy('category.id')
  .map(group => ({
    category: _.head(group).category,
    products: _.map(group, o => _.omit(o, 'category'))
  }))
  .value()

console.log(result)

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Or the _.flow() function equivalent with lodash/fp:

const { flow, groupBy, map, head, omit } = _

const fn = flow(
  groupBy('category.id'),
  map(group => ({
    category: head(group).category,
    products: map(omit('category'), group)
  }))
)

const data = [{"id":1,"name":"produto1","category":{"id":1,"name":"shirts","description":"super roupa"}},{"id":2,"name":"produto2","category":{"id":1,"name":"shirts","description":"super roupa"}},{"id":3,"name":"produto3","category":{"id":2,"name":"jackets","description":"super jackets"}},{"id":4,"name":"produto4","category":{"id":2,"name":"jackets","description":"super jackets"}}]

const result = fn(data)

console.log(result)

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