Ramda Get values from nested objects inside array

Question

I am trying to get values from a nested object using Ramda but I just started to use it. To get the testArray I used:

R.find(R.propEq('type', 'checklist'))((data))

Data is another array with different types but I need to focus only on 'checklist' type. I would like to get only items which have property "checked": true.

This is my array which I am trying to transform.

const testArray = [{
  "type": "checklist",
  "data": {
    "items": [
      { "id": "r-1", "checked": true },
      { "id": "r-2", "checked": false }
    ]
  }
}]

Edit: I made another step using:

R.path(['data', 'items'])

I got only items that I can simply filter. But I am not sure if it is the correct way to do that.

Any help will be appreciated.

Scott Sauyet · Accepted Answer · 2020-04-28 12:51:35Z

3

Here's one approach:

const checkedItems = pipe (
  find (propEq('type', 'checklist')),
  defaultTo ({data: {items: []}}),
  path (['data', 'items']),
  filter (prop ('checked'))
)

const testArray = [{type: "checklist", data: {items: [{id: "r-1", checked: true }, {id: "r-2", checked: false}]}}]

console .log (
  checkedItems (testArray)
)

<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.27.0/ramda.js"></script>
<script>const {pipe, find, propEq, defaultTo, path, filter, prop} = R</script>

Ramda (disclaimer: I'm one of its authors) is designed around this idea of a functional pipeline, where the result of one call is piped into the next. Here we use the propEq you started with, pipe it to a defaultTo call, which gives a sensible default if the previous step finds nothing, then to the path statement you used, and then finally to a filter call, which keeps only those where the checked property is true.

If you're absolutely certain about your data, you can skip the defaultTo step.

The filter call could also be filter (propEq ('checked', true)), but since prop ('checked') whould be returning a boolean, I went with the simpler version.

answered Apr 28, 2020 at 12:51

Scott Sauyet

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1 Comment

omygoodness Over a year ago

Thank you. So I was close... :D

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