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javascriptfilterlodash

How to filter keys of an object with lodash?

I have an object with some keys, and I want to only keep some of the keys with their value?

I tried with filter:

const data = {
  aaa: 111,
  abb: 222,
  bbb: 333
};

const result = _.filter(data, (value, key) => key.startsWith("a"));

console.log(result);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>

But it prints an array:

[111, 222]

Which is not what I want.

How to do it with lodash? Or something else if lodash is not working?

Solution

  • Lodash has a _.pickBy function which does exactly what you're looking for.

    var thing = {
  "a": 123,
  "b": 456,
  "abc": 6789
};

var result = _.pickBy(thing, function(value, key) {
  return _.startsWith(key, "a");
});

console.log(result.abc) // 6789
console.log(result.b)   // undefined
    <script src="https://cdn.jsdelivr.net/lodash/4.16.4/lodash.min.js"></script>