get ids from json array

Question

I'm having a hard time trying to figure out how to iterate through json data to gather all the duplicate Id's to display the "dateTimes" that match their Id.

for example, I need it to display similar to this: Regal Broward Stadium 12 & RPX 2017-09-20 13:30 2017-09-20 16:00 2017-09-20 18:35

Flipper's Hollywood Cinema 10 2017-09-20 12:40 2017-09-20 14:40 2017-09-20 16:35

I wrote a function that I think that would work for just one Id but I don't know how I would find all the matching Id's to display the dateTimes.

getShowtimes(data){

    var json = JSON.parse(data);

    for(let i = 0; json.theater.id; i++){

        if (json[i].theatre.id == 10863){

            json[i].theatre.dateTime;

        }

    }

}

right now i'm not using the function to display the results(cause it doesn't work ), I'm just using the code below.

<div class="showtime" *ngFor="let shows of show">
    <div *ngFor="let detail of shows.showtimes>
        <div *ngIf="detail.theatre.id == 10863">
            {{detail.theatre.name}}{{detail.dateTime}}
        </div>
    </div>
</div>

you need to take the flat array data and do a group by id. you can use library like lodash for this purpose or write a native javascript method for grouping https://stackoverflow.com/questions/14446511/what-is-the-most-efficient-method-to-groupby-on-a-javascript-array-of-objects — spiritwalker, Sep 20 '17 at 01:34

score 3 · Answer 1 · answered Feb 24 '22 at 20:38

This could be a good solution:

let employees = [
    { "id": 1, "firstName":"John", "lastName":"Doe" },
    { "id": 2, "firstName":"Anna", "lastName":"Smith" },
    { "id": 3, "firstName":"Anna", "lastName":"Smith" },
    { "id": 4, "firstName":"Peter", "lastName":"Jones" }
];
    
let employeeIds = [];
employeeIds.push(...employees.map(emp => emp.id));
console.log(employeeIds);

output of employeeIds is [ 1, 2, 3, 4 ]

let duplicateNames = employees
     .map(emp => emp['firstName'])
     .map((emp, i, final) => final.indexOf(emp) !== i && i)
     .filter(obj=> employees[obj])
     .map(emp => employees[emp]["firstName"])
console.log(duplicateNames);

output of duplicateNames is [ 'Anna' ]

score 1 · Answer 2 · answered Sep 20 '17 at 03:04

Maybe this can help:

const data = [
    { theatre: { id: "10863", name: "Regal Broward Stadium 12 & RPX", dateTime: "2017-09-20T13:30" }},
    { theatre: { id: "10863", name: "Regal Broward Stadium 12 & RPX", dateTime: "2017-09-20T13:30" }},
    { theatre: { id: "10863", name: "Regal Broward Stadium 12 & RPX", dateTime: "2017-09-20T16:00" }},
    { theatre: { id: "10863", name: "Regal Broward Stadium 12 & RPX", dateTime: "2017-09-20T18:35" }},
    { theatre: { id: "10863", name: "Regal Broward Stadium 12 & RPX", dateTime: "2017-09-20T21:00" }},
    { theatre: { id: "4089", name: "Flipper's Hollywood Cinema 10", dateTime: "2017-09-20T12:40" }},
    { theatre: { id: "4089", name: "Flipper's Hollywood Cinema 10", dateTime: "2017-09-20T14:40" }},
    { theatre: { id: "4089", name: "Flipper's Hollywood Cinema 10", dateTime: "2017-09-20T16:35" }}
];

let result = {};

data.forEach((item) => {
  if (!result.hasOwnProperty(item.theatre.id)) {
    result[item.theatre.id] = {
        name: item.theatre.name,
        dates: item.theatre.dateTime
    };
  } else {
    result[item.theatre.id].dates = result[item.theatre.id].dates + ' ' + item.theatre.dateTime;
  }
});


Object.keys(result).forEach((key) => {
  console.log(`${result[key].name} ${result[key].dates}`)
});

the console is telling me that data.forEach is not a function — Jason, Sep 20 '17 at 23:15
Can you tell me more about how your `data` looks like?? @Jason — kevguy, Sep 22 '17 at 06:32

score -1 · Answer 3 · edited Sep 20 '17 at 02:33

-1

Use like this detail.theatre.id === '10863' because its a string,

<div *ngIf="detail.theatre.id === '10863'">
    {{detail.theatre.name}}{{detail.dateTime}}
</div>

edited Sep 20 '17 at 02:33

Axel

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answered Sep 20 '17 at 01:29

Sajeetharan

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get ids from json array

3 Answers3