Lodash过滤器由object的object

Question

How to filter items by type?

const items = {
        'someHash0': {
          type: 'foo',
          name: 'a'
        },
        'someHash1': {
          type: 'foo',
          name: 'b'
        },
        'someHash2': {
          type: 'foo',
          name: 'c'
        },
        'someHash3': {
          type: 'baz',
          name: 'd'
        },
      };

I want to filter by type=foo and get that result:

const items = {
        'someHash0': {
          type: 'foo',
          name: 'a'
        },
        'someHash1': {
          type: 'foo',
          name: 'b'
        },
        'someHash2': {
          type: 'foo',
          name: 'c'
        }
      };

I tryied with

 return _.mapValues(pairs, function (item) {
     return (item.type === 'foo') ?? item
})

but it returns true/false instead of the whole object

Answer 1

map in general is for editing iterated inputs, so it's not what you need.

You can do like this:

let result = _.filter(items, x => x.type === 'foo')

If you need to keep the same keys you could do it like this:

let result = _.pickBy(items, x => x.type === 'foo')

Answer 2

A filter would be enough if you didn't need to re-add the numbering. In that case, you can still get away rather easily by combining reduce and filter , as follow:

 const items = { '0': { type: 'foo', name: 'a' }, '1': { type: 'foo', name: 'b' }, '2': { type: 'foo', name: 'c' }, '3': { type: 'baz', name: 'd' }, }; const mapped = _.reduce(_.filter(items, (item) => item.type === 'foo'), (acc, item, index) => { acc[index] = item return acc }, {}) console.log(mapped)

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