Angular2,Typescript:How to push array of objects into another array of objects with only a few fields of the object

Question

I know how to operate on array of objects but never had the necessity to push one array data into another. I need to push an array of objects into another array with only 2 fields of the object. Right now my object format is somewhat like this

data: [{
        "name": "Btech",
        "courseid": "1",
        "courserating": 5,
        "points": "100",
        "type": "computers"
    },
   {
        "name": "BCom",
        "courseid": "2",
        "courserating": 5,
        "points": "100",
        "type": "computers"
    }];

I want to push this into another array but I want only courseid and name in the object. I've read that we need to initialise the object in the constructor, use slice() and a few other functions and then push but I don't know how can I do it for mine since I need to push one array data into another.Kindly someone help me in this regard.

Supposing `other` is the other array, you can do it: `data.map(item => { return { courseid: item.courseid, name: item.name } }).forEach(item => other.push(item));` — Diullei, Apr 06 '17 at 16:36

score 22 · Accepted Answer · answered Apr 06 '17 at 16:37

22

You're looking for the array map() method:

const newArray = array.map(o => {
  return { name: o.name, courseid: o.courseid };
});

answered Apr 06 '17 at 16:37

JB Nizet

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91
1,224
1,255

Diullei · Answer 2 · 2017-04-06T16:44:45.677

11

Try this:

let data = [{
    "name": "Btech",
    "courseid": "1",
    "courserating": 5,
    "points": "100",
    "type": "computers"
},
{
    "name": "BCom",
    "courseid": "2",
    "courserating": 5,
    "points": "100",
    "type": "computers"
}];

let other = []; // your other array...

data.map(item => {
    return {
        courseid: item.courseid,
        name: item.name
    }
}).forEach(item => other.push(item));

console.log(JSON.stringify(other))
// => [{"courseid":"1","name":"Btech"},{"courseid":"2","name":"BCom"}]

edited Apr 06 '17 at 16:44

answered Apr 06 '17 at 16:39

Diullei

11,420
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Thanks a lot. It worked.Could you tell me how can deepcopy or clone an array in typescript ? – Impromptu_Coder Apr 07 '17 at 10:20

score 5 · Answer 3 · answered Apr 06 '17 at 17:32

5

You can simply do it like this.

//assign your array of object to variable

var youArray:Array<any>= [{
    "name": "Btech",
    "courseid": "1",
    "courserating": 5,
    "points": "100",
    "type": "computers"
},
{
    "name": "BCom",
    "courseid": "2",
    "courserating": 5,
    "points": "100",
    "type": "computers"
}];

var resultArray:Array<any>=[] //empty array which we are going to push our selected items, always define types 

youArray.forEach(i=>{ 
   resultArray.push(
   {
    "name":i.name,
    "courseid":i.courseid
   });
});

console.log(resultArray)

if you still have doubts about this.please follow this url

answered Apr 06 '17 at 17:32

isuruAb

2,202
5
26
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Could you tell me how to deepcopy or clone an array in typescript ? – Impromptu_Coder Apr 07 '17 at 10:20
@Impromptu_Coder did u see this. http://stackoverflow.com/questions/35504310/deep-copy-an-array-in-angular-2-typescript – isuruAb Apr 07 '17 at 10:28

score 0 · Answer 4 · answered Aug 25 '17 at 12:01

Map to a returning JSON data, subscribe it to an existing array or an empty one. #typescript

  let pictimeline= []; 
    var timeline = this.picService.fetchtimeline(this.limit)


.map((data : Response) => data.json())
    .subscribe(pictimeline=> this.pictimeline = pictimeline);


console.log(this.pictimeline);

Angular2,Typescript:How to push array of objects into another array of objects with only a few fields of the object

4 Answers4