Transform javascript array with objects with lodash

Question

I'm wondering what the best way would be to transform my javascript array with objects. I have tried making a fancy chain with lodash but I can't figure it out.

I need to format the data this way because of the way the backend works.

// from:
var something = [
  {
    name: 'foo',
    stuff: [
      {
        id: 1
      },
      {
        id: 2
      },
      {
        id: 3
      }
    ]
  },
  {
    name: 'bar',
    stuff: []
  },
  {
    name: 'baz',
    stuff: [
      {
        id: 7
      },
      {
        id: 8
      }
    ]
  }
];

// to:
var transformed = [
  {
    name: 'foo',
    included: {
      included: [1, 2, 3]
    }
  },
  {
    name: 'bar',
    included: {
      included: []
    }
  },
  {
    name: 'baz',
    included: {
      included: [7, 8]
    }
  }
];

You really need to have added the code you've tried.

Andy
– Andy

2016-04-06 15:40:24 +00:00
Commented Apr 6, 2016 at 15:40 — Andy
– Andy, Commented Apr 6, 2016 at 15:40

ssube · Accepted Answer · 2016-04-06 15:38:12Z

2

You can do this quite concisely with two map calls (the array built in or lodash's map), one nested to handle the "included" array within each object:

const transformed = something.map(it => {
  return {
    name: it.name,
    included: {
      included: it.stuff.map(thing => thing.id)
    }
  };
});

answered Apr 6, 2016 at 15:38

ssube

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Comments

cl3m · Accepted Answer · 2016-04-06 15:45:30Z

1

No need for lodash, just use the Array.prototype.map function:

// Sorry no fancy ES6 => here :S
var res = something.map(function(item) {
  item.included = {included : item.stuff.map(function(i) {return i.id})}
  delete(item.stuff)
  return item
})

Per @ssube's comment:

var res = something.map(function(item) {
  return {
    included : {included : item.stuff.map(function(i) {return i.id})},
    name: item.name
  }
})

See this fiddle

edited Apr 6, 2016 at 15:45

answered Apr 6, 2016 at 15:39

cl3m

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1 Comment

ssube Over a year ago

This is going to mutate the original objects, which map should not do (see this output). Rather than modifying and returning item, you probably want to return a new object with the right properties.

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