Generate Array Based on Start and Limits

Introduction

When you are configuring for integration, there may be a need to create an array with configurable start and end limits.

For example, you want to create an array with the objects has id property starting from 4 to 7 through its objects, as below:

```
[ 
  { 
    "id": 4 
  }, 
  { 
    "id": 5 
  }, 
  { 
    "id": 6 
  }, 
  { 
    "id": 7 
  } 
] 
```

In this guide, we will show you how to do it within an entity transformer configuration.

Steps

  1. First, you must include or set the limits (start and end) in the entity data. Example:

    { 
      "start": 4, 
      "end": 7 
    } 
    
  2. Chain multiple entity transformers is recommended because you will have more than one entity transformer if you create it in a single entity transformer.

  3. Then, inside a Data, transform data using mappers and conditions, you need to subtract the end limit from the start limit using a value setter and an operator mapper (subtraction) to get the difference. To create an array from 4 to 7, add the Prepared Operator mapper (Addition) and set the Left to 1 (number).

  1. Next, after getting the difference, it should be converted to an array where the length equals to the difference using List: Fill the list with a value mapper and set the Length to &@, which represents the difference property’s current value. When the difference is 4, the result is an array of integers, i.e., [“4”, “4”, “4”, “4”].

  1. Then, the array should be converted to an array of objects using the Move data between accessors. The Source accessor is a Key accessor, and the Destination accessor is the Structure accessor. So, the array would be something like this:

    {
      "difference": [ 
        { 
          "index": "0", 
          "value": 3 
        }, 
        { 
          "index": "1", 
          "value": 3 
        }, 
        { 
          "index": "2", 
          "value": 3 
        } 
      ]
    }
    

  1. Then, we can copy the start limit to all the objects using the Recursively copy values to children transformer so that every object will have the start limit, such as below.

    {
      "difference": [
        { 
          "index": "0", 
          "value": 3, 
          "start": 4 
        }, 
        { 
          "index": "1", 
          "value": 3, 
          "start": 4 
        }, 
        { 
          "index": "2", 
          "value": 3, 
          "start": 4 
        } 
      ]
    }
    

  1. Then, inside a Node, transform nodes, you need to create a new attribute, for example, id, where the value is the sum of the index and start values.

  1. Then you can remove other attributes, except id, using the Key Filter.

  1. Finally, in the data transformer (outside the node) use the List Mapper and the Get values mapper to tidy up the data structure.

And here is the final result.

```
{ 
  "start": 4, 
  "end": 7, 
  "difference": [ 
    { 
      "id": 4 
    }, 
    { 
      "id": 5 
    }, 
    { 
      "id": 6 
    }, 
    { 
      "id": 7 
    } 
  ] 
} 
```