Lodash:Getting new array with mulitple matches in JSON

问题

I have a nested JSON look like this

[
{arrivalTime: "10:30 PM"
 availableSeats: 23
boardingPoints: [{id: "3882"
location: "abc"
time: "02:30PM"},{id: "3882"
location: "xyz"
time: "02:30PM"}]
busType: "Scania Metrolink"
commPCT: 8
departureTime: "1:15 PM"
droppingPoints: null
},
{arrivalTime: "10:30 PM"
 availableSeats: 23
boardingPoints: [{id: "3882"
location: "def"
time: "02:30PM"},{id: "3882"
location: "jkl"
time: "02:30PM"}]
busType: "Scania "
commPCT: 8
departureTime: "1:15 PM"
droppingPoints: null
}    
]

From this i want to get new array that matches a condtion. Here is it

1.get the new array with only the user specified location in boardingPoints object.

eg-a:Suppose the location value is xyz it will return only the JSON with that contains the location xyz only in the boardingPoints object.

output

eg-b:Suppose location value is xyz and def it should returns only with JSON that contains the above two locations only in the boardingPoints object.

output

{arrivalTime: "10:30 PM" availableSeats: 23 boardingPoints: [{id: "3882" location: "abc" time: "02:30PM"},{id: "3882" location: "xyz" time: "02:30PM"}] busType: "Scania Metrolink" commPCT: 8 departureTime: "1:15 PM" droppingPoints: null }, {arrivalTime: "10:30 PM" availableSeats: 23 boardingPoints: [{id: "3882" location: "def" time: "02:30PM"},{id: "3882" location: "jkl" time: "02:30PM"}] busType: "Scania " commPCT: 8 departureTime: "1:15 PM" droppingPoints: null }

I know this may be implemented using lodash but i don't know how to do it

Currently i know about only matches in lodash but i don't know how can i use this in my case.

    var users = [
      { 'user': 'barney', 'age': 36, 'active': true },
      { 'user': 'fred',   'age': 40, 'active': false }
    ];  
    _.filter(users, _.matches({ 'age': 40}));
// → [{ 'user': 'fred', 'age': 40, 'active': false }]

Is it possible with native method in javascript?

回答1:

You can use a series of lodash calls with some logic to get the expected results. Something like this:

var _ = require('lodash');

var result = [
    {
        arrivalTime: "10:30 PM",
        availableSeats: 23,
        boardingPoints: [{
            id: "3882",
            location: "abc",
            time: "02:30PM"
        },{
            id: "3882",
            location: "xyz",
            time: "02:30PM"
        }],
        busType: "Scania Metrolink",
        commPCT: 8,
        departureTime: "1:15 PM",
        droppingPoints: null,
    },
    {
        arrivalTime: "10:30 PM",
        availableSeats: 23,
        boardingPoints: [{
            id: "3882",
            location: "def",
            time: "02:30PM"
        },{
            id: "3882",
            location: "jkl",
            time: "02:30PM"
        }],
        busType: "Scania ",
        commPCT: 8,
        departureTime: "1:15 PM",
        droppingPoints: null
    }
];
var locations = ['xyz'];

var f = _.filter(result, function(obj) {
    var value = _.map(obj.boardingPoints, 'location');       
    var i, len;

    for (i = 0, len = locations.length; i < len; i++) {
        if (_.indexOf(value, locations[i]) >= 0) {
            return true;
        }
    }
    return false;
});

console.log(f);  // result is your eg-a

when

locations = ['xyz', 'def'];

the result will be your eg-b

Another approach to the solution is to chain the calls with intersection():

var f = _.filter(result, function(obj) {
  return _.chain(obj.boardingPoints).map('location').intersection(locations).value().length > 0;
});

回答2:

var result = _.filter(yourArray, function(item) {
    return _.size(_.intersection(['xyz', 'def'], _.map(item.boardingPoints, 'location')));
});

https://jsfiddle.net/qeaabov9/2/

来源：https://stackoverflow.com/questions/35519293/lodashgetting-new-array-with-mulitple-matches-in-json

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