CODEWITHSUNDEEP
javascriptarrays
ChrisM
ChrisM

Reputation: 716

Javascript - How to filter an array of Objects by a Parameter

I have a variable which is an array of comments.

$scope.numOfCommentsCoupon

What i would like to have is a variable which is a count of the Comments inside the array that have a "couponId" of a certain value.

Here is the Comment Model

    var CommentSchema = new Schema({

    created: {
        type: Date,
        default: Date.now
    },
    couponId: {
        type: String,
        trim: true
    }

});

So i need to filter it and then count it but im not sure how to.

Upvotes: 0

Views: 53

Answers (3)

Jesús López
Jesús López

Reputation: 9221

Youd could use reduce method on the array to get the count of coupons whose couponId is equals to a given string:

var comments = [
    {
        couponId : "1"
    },
    {
        couponId : "2"
    }
];

var couponIdToCount = "2";

var count = comments.reduce(function(previous, current) {
    return current.couponId == couponIdToCount ? previous + 1: previous;
}, 0);

console.log(count)

Upvotes: 0

Ryuu
Ryuu

Reputation: 606

I think I follow what you're trying to do and you can use array.filter

It would look like this:

var currentCouponId = 1;
var matching = yourArray.filter(function (element) { return element.couponId == 1; });
console.log(matching.length);

Upvotes: 0

Trash Can
Trash Can

Reputation: 6824

If you have an array of comments, to do that, you could do something like this

var count = 0;
comments.filter(function(comment,index,array){
    if (comment.couponId === "some_value") {
        count++;
    }
});

Or you could just iterate over it using the for loop. Pretty straightforward stuff to implement

Upvotes: 2

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