Ramda: How can I filter data with nested objects?

Question

const articles = [
    {title: 'title 1', published: false, pages: 30, tags: {name: 'work', id: 1, visibility: "everyone"}},
    {title: 'title 2', published: false, pages: 25, tags: {name: 'home', id: 3, visibility: "myself"}},
    {title: 'title 3', published: true, pages: 30, tags: {name: 'vacation', id: 5, visibility: "myself"}}
];

My JSON data looks something like this and I need to filter based on the value where published is true and visibility is myself. How can I achieve this in efficient manner? Would appreciate any help with this.

So far I have only been able to filter using single attribute

  R.filter(R.propEq("published", false))(articles);

mzedeler · Accepted Answer · 2020-03-19T08:33:47.770

4

Something like this:

R.filter(
  R.allPass([
    R.propEq("published", false),
    R.pathEq(["tags", "visibility"], "myself")
  ])
)(articles);

edited Mar 19 '20 at 08:33

answered Mar 17 '20 at 18:26

mzedeler

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1

Yes, and if you need more than two predicates, use `R.allPass` in place of `R.and`. – Scott Sauyet Mar 17 '20 at 19:02
1

shouldn't it be `both` instead of `and`? `R.and` doesn't seem to take predicates https://ramdajs.com/docs/#and – Hitmands Mar 18 '20 at 09:11
1

Just double-checked, can confirm current implementation is not working. @mzedeler could you please review it? – Hitmands Mar 18 '20 at 09:25
I've never been happy that Ramda uses `and` and `or` for the equivalent of `&&` and `||`. In many ways I would rather that they serve the role that `both` and `either` now do. – Scott Sauyet Mar 18 '20 at 15:41
Sorry guys. Fixed! – mzedeler Mar 19 '20 at 08:34

score 2 · Answer 2 · answered Mar 18 '20 at 09:14

You could use a spec object:

const predicate = R.where({
  published: R.equals(true),
  tags: R.where({
    visibility: R.equals('myself'),
  }),
});


// ==

const data = [
  {title: 'title 1', published: false, pages: 30, tags: {name: 'work', id: 1, visibility: "everyone"}},
  {title: 'title 2', published: false, pages: 25, tags: {name: 'home', id: 3, visibility: "myself"}},
  {title: 'title 3', published: true, pages: 30, tags: {name: 'vacation', id: 5, visibility: "myself"}}
];

console.log(
  R.filter(predicate, data),
);

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.0/ramda.js" integrity="sha256-buL0byPvI/XRDFscnSc/e0q+sLA65O9y+rbF+0O/4FE=" crossorigin="anonymous"></script>

Ramda: How can I filter data with nested objects?

2 Answers2