outerJoin

outerJoin(Array<L>, Array<R>, (leftValue: L) -> String, (rightValue: R) -> String): Array<{ l?: L, r?: R }>

Joins two array of objects by a given ID criteria.

outerJoin returns an array with all the left items, merged by ID with the right items in cases where any exist, and it returns right items that are not present in the left.

Introduced in DataWeave 2.2.0. Supported by Mule 4.2 and later.

Parameters

Name Description

Name	Description
`left`	The left-side array of objects.
`right`	The right-side array of objects.
`leftCriteria`	The criteria used to extract the ID for the left collection.
`rightCriteria`	The criteria used to extract the ID for the right collection.

left

The left-side array of objects.

right

The right-side array of objects.

leftCriteria

The criteria used to extract the ID for the left collection.

rightCriteria

The criteria used to extract the ID for the right collection.

Example

This example shows how join behaves. Notice that the output includes objects where the values of the input user.id and product.ownerId match, and it includes objects where there is no match for the value of the user.id or product.ownerId.

Source

 %dw 2.0
 import * from dw::core::Arrays
 var users = [{id: "1", name:"Mariano"},{id: "2", name:"Leandro"},{id: "3", name:"Julian"},{id: "5", name:"Julian"}]
 var products = [{ownerId: "1", name:"DataWeave"},{ownerId: "1", name:"BAT"}, {ownerId: "3", name:"DataSense"}, {ownerId: "4", name:"SmartConnectors"}]
 output application/json
 ---
 outerJoin(users, products, (user) -> user.id, (product) -> product.ownerId)

Output

[
  {
    "l": {
      "id": "1",
      "name": "Mariano"
    },
    "r": {
      "ownerId": "1",
      "name": "DataWeave"
    }
  },
  {
    "l": {
      "id": "1",
      "name": "Mariano"
    },
    "r": {
      "ownerId": "1",
      "name": "BAT"
    }
  },
  {
    "l": {
      "id": "2",
      "name": "Leandro"
    }
  },
  {
    "l": {
      "id": "3",
      "name": "Julian"
    },
    "r": {
      "ownerId": "3",
      "name": "DataSense"
    }
  },
  {
    "l": {
      "id": "5",
      "name": "Julian"
    }
  },
  {
    "r": {
      "ownerId": "4",
      "name": "SmartConnectors"
    }
  }
]