Forum Discussion

mohamadelmardin's avatar
mohamadelmardin
New Contributor III
9 years ago

How to render distinct elements only in an array with duplicates

I have a JSON document that has inside an array with duplicate values such as [1,1,3,3,6,1,2,1,2,100]. I am trying to transform/map it from source into target by returning only the distinct values s...
sample_pipeline
tstack's avatar
tstack
Former Employee
9 years ago

The expression language is a subset of JavaScript, so you can usually start by looking for JavaScript-based solutions.

In this case, take a look at this post:

The first answer has the simplest solution. The only change you have to make is to convert the callback function to use the arrow-function syntax, like so:

$arr.filter((item, pos, a) => a.indexOf(item) == pos)

mohamadelmardin's avatar
mohamadelmardin
New Contributor III
9 years ago

Thank you. That was helpful :+1:

    • Anjali's avatar
      Anjali
      New Contributor
      5 years ago

      Can you please explain how this filter function is working? what is item , pos and a here and how there are related to each other and functioning?

      • cjhoward18's avatar
        cjhoward18
        Employee
        5 years ago

        Hi @Anjali

        item is the current item it is iterating over in the array, pos is the position in the array for this item and a is the array itself.

        The expression to remove duplicates is using the indexOf() to collect a single instance of each unique element in the filter() method since indexOf() returns the first found index for each unique value each time.