joinBy joinBy(@StreamCapable elements: Array<StringCoerceable>, separator: String): String Merges an array into a single string value and uses the provided string as a separator between each item in the list. Note that joinBy performs the opposite task of splitBy. Parameters Name Description elements The input array. separator A String used to join elements in the list. Example This example joins the elements with a hyphen (-). Source %dw 2.0 output application/json --- { "hyphenate" : ["a","b","c"] joinBy "-" } Output { "hyphenate": "a-b-c" } joinBy(n: Null, separator: Any): Null Helper function that enables joinBy to work with a null value. Introduced in DataWeave version 2.4.0.