skipNulls option for queryString.stringify

[goodwin64]

Hi!

I am now comparing 2 libs for future use on my project: qs and query-string.
The second one has some advantages like encoding/decoding booleans and numbers which are important for me. But the 1st one has skipNulls option which allows to skip null and undefined values:

const obj1 = {
  a: 1,
  b: '2',
  c: [3, 4, 5],
  d: true,
  e: 'just string',
  f: null,
  g: undefined,
};

// qs
// can skip null/undefined values
const ex2 = qs.stringify(obj1, {
  addQueryPrefix: true,
  arrayFormat: 'comma',
  skipNulls: true,
});
const ex3 = qs.parse(ex2, {
  parseArrays: true,
  comma: true,
  ignoreQueryPrefix: true,
});

// query-string
// can store numbers and booleans
const ex4 = queryString.stringify(obj1, {
  strict: true,
});
const ex5 = queryString.parse(ex4, {
  parseNumbers: true,
  parseBooleans: true,
});

console.log('ex2', ex2);
console.log('ex3', ex3);
console.log('ex4', ex4);
console.log('ex5', ex5);

Does it sound reasonable to implement this option?

[sindresorhus]

Sure, PR welcome. For the person that wants to work on this, don't forget to add docs, tests, and update the TypeScript definition.

[sindresorhus]

I think the option should be skipNullAndUndefined to make it clear what it does.

[FredrikAugust]

I'll get to work on this now.

[goodwin64]

@sindresorhus PR is ready. Looking forward it to be merged.

[MichaelDeBoey]

@sindresorhus undefined is already skipped by default.

[ashtonian]

3 separate configurable options would be very nice inspired by https://www.npmjs.com/package/qs.

{
"skipNulls" : true|false, 
"skipUndefined": true|false, // currently default
"skipEmptyStrings":true|false
}

[sindresorhus]

@ashtonian That seems a bit over the top in configurability. You would need to present arguments for why those are needed with actual use-cases.

[ashtonian]

@sindresorhus - ha it may be a bit over the top.

For separating undefined and nulls I would prefer this because sometimes they are used differently in the back end. I've never wanted to pass undefined, but I have wanted to pass nulls, sometimes to use it as a value, or sometimes to clear a relationship/field in an edit form submission.

For the skipEmptyStrings I'm mainly using this for search forms, via a vue hook to store search state in the query and via an axios hook to submit said search queries to an api.

// ... 
    data () {
      return {
        searchForm: {
          someFieldA:"",
          someFieldB:undefined,
          someFieldC:null
        }
      }
// ...
this.$router.replace({
  query: this.searchForm // passes "" strings around for optional fields
})
// ... 
this.axios.get("/some/api/search",{query:this.searchForm})

I have certain 3rd part input components that self parse to a respective type that is bound to my components data objects this.searchForm. Sometimes their default values specifically <b-input type="number"> from buefy will default to "" and then that gets forwarded on in place of a number and causes problems.

[mikestecker]

Stumbled on this thread looking for the same thing. skipEmptyStrings as described above by @ashtonian is exactly what I'm looking for. I'm using the query string in a search form as well, however I'd love to see it as a parse option, this way I can just strip it out of the object if it is ""

[mikestecker]

I found a workaround, but it would be great to have this built-in

Here's my workaround:

    const routerQuery = queryString.parse(router.asPath.split(/\?/)[1], {
      parseNumbers: true,
      parseBooleans: true
    });
    const removeFalsy = obj => {
      let newObj = {};
      Object.keys(obj).forEach(prop => {
        if (obj[prop]) {
          newObj[prop] = obj[prop];
        }
      });
      return newObj;
    };

    const query = removeFalsy(routerQuery);