如何使用lodash使用值数组过滤嵌套对象？

Question

I have the following data:

var jobs = [
{
 job_type: "Part Time",
 latitude: 49.545068,
 longitude: 0.760518,
 title: "reiciendis",
 industry: [
  {
    id: 1,
    name: "development" },
  { 
    id: 2,
    name: "design"
  }
 ]},
{
 job_type: "Full Time",
 latitude: 51.545068,
 longitude: 0.460518,
 title: "auteas",
 industry: [
  {
    id: 1,
    name: "development" },
  { 
    id: 2,
    name: "testing"
  }
 ]

and I'd like to try and filter the results based on a users search parameters, namely the choice of industries for a job search, which populate an array:

var jobchoices = ["testing", "design"];

my lodash filter so far looks like this:

var self = this

return _.filter(this.jobs, function(item) {
    return _.filter(item.industry, function(obj) {
        return _.some(self.jobchoices, obj.name);
    });
});

but it returns true for all jobs. This is my first time using lodash. What am I doing wrong? Secondly, could I continue chaining in this fashion to filter by another user choice, say by job type?

Answer 1

You can use _.filter for the main array you are trying to retrieve as the end result and then use _.chain with _.map and _.intersection to filter the internal the objects array.

Something like the code bellow should suffice, although it is not pretty.

var self = this;

_.filter(jobs, function(job) { 

  return _.chain(job.industry)
    .map('name')
    .intersection(self.jobchoices)
    .size()
    .gt(0)
    .value() 
})

(Tested only with latest lodash - v4.16.4)

Answer 2

It should return true for all jobs, because both jobs in your example data jobs have matching industry items. If you change your jobchoices array to have an item (or multiple items) that only match one of your jobs , that could look something like this (vanilla JS):

var matches = jobs.filter(function(job) {
  return job.industry.some(function(industry) {
    return jobchoices.indexOf(industry.name) > -1;
  });
});

Or the ES6 equivalent:

let matches = jobs.filter(({industry} => industry.some(({name}) => jobchoices.includes(name)));

As to where you are going wrong, your top-level _.filter is returning another _.filter (which will return an array - and is truthy - therefore all items will be returned). You should be able to modify your original code return whether the inner _.filter call's length is > 0 to remedy:

return _.filter(this.jobs, function(item) {
    var matchingIndustries = _.filter(item.industry, function(obj) {
        return _.some(self.jobchoices, obj.name);
    });
    return matchingIndustries.length > 0;
});