leftJoin
leftJoin<L <: Object, R <: Object>(left: Array<L>, right: Array<R>, leftCriteria: (leftValue: L) -> String, rightCriteria: (rightValue: R) -> String): Array<{ l: L, r?: R }>
Joins two arrays of objects by a given ID criteria.
leftJoin returns an array all the left items, merged by ID with any right
items that meet the joining criteria.
Introduced in DataWeave version 2.2.0.
Parameters
| Name | Description |
|---|---|
|
The left-side array of objects. |
|
The right-side array of objects. |
|
The criteria used to extract the ID for the left collection. |
|
The criteria used to extract the ID for the right collection. |
Example
This example shows how join behaves. Notice that it returns all objects from
the left-side array (left) but only joins items from the right-side array
(right) if the values of the left-side user.id and right-side
product.ownerId match.
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
---
leftJoin(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"
}
}
]