Explain about $, $$, $$$ in mapobject ? in MuleSo...

 Explain about $, $$, $$$ in mapobject ? in MuleSo...

In MuleSoft 4 DataWeave, the symbols $, $$, and $$$ are used within the mapObject function to access and manipulate key-value pairs within an object. They represent different aspects of each pair:

$ (value):

• Represents the value associated with the current key-value pair.

• This is the primary element you want to access or transform within the mapObject function.

$$ (key):

• Represents the key of the current key-value pair.

• This can be useful for dynamic key construction or accessing specific keys within the object.

$$$ (index):

• Represents the index of the current key-value pair within the object.

• This can be used for ordering or filtering elements based on their position.

Example:

%dw 2.0
output application/json
---
payload mapObject (item, index) -> {
  upperCaseName: $.name.toUpperCase(),
  reversedKey: $$ + "Reversed",
  position: $$$ + 1
}

In this example:

• $.name accesses the value associated with the name key within each item.

• $$ + "Reversed" dynamically constructs a new key called Reversed for each item.

• $$$ + 1 adds 1 to the index to start numbering from 1 instead of 0.

Key Points:

• You can use these symbols individually or combine them in expressions within the mapObject function.

• These symbols are only valid within the mapObject function and cannot be used standalone in other contexts.

• Using these symbols provides flexibility and control when manipulating key-value pairs in MuleSoft 4 DataWeave.

Additional Notes:

• You can access nested objects within the value using dot notation like $.address.city.

• You can use conditional logic within the mapObject function to modify values or filter key-value pairs based on specific criteria.

• DataWeave provides other functions like map and filter that can also be used to manipulate arrays and objects, but mapObject offers more fine-grained control over individual key-value pairs.

I hope this explanation clarifies the roles of $, $$, and $$$ in the mapObject function in MuleSoft 4 DataWeave. Feel free to ask if you have any further questions or require more specific examples based on your use case!