Transmute Developer Guide v0.5.1

Quickstart

Open the Playground, paste your JSON into the Payload panel, then write a DSL expression in the Script editor.

Copyoutput application/json
---
payload.users filter ($.age > 25) map $.name

▶ Try in Playground

Playground UI Tour

① Input Explorer

Located on the left. Contains the Payload panel (your input JSON) and optional named Variables.

② Script Editor Updated

A unified code editor in the center with live line numbers and syntax highlighting.

③ Output Panel

④ Autocomplete New

As you type, a suggestion popup appears. The first item is always pre-selected — press Enter immediately to accept it.

Navigate with ↑ ↓, accept with Enter or Tab, dismiss with Esc.

⑤ Log Viewer

Collapsible panel at the bottom — shows output from log() and trace() calls. Click ▶ Logs to expand.

Script Structure

Copy// Header: output directive + variable/function definitions
output application/json
var active = payload.users filter $.age > 25
fun greet(name) = "Hello, " ++ name

---

// Body: the expression to evaluate
{count: sizeOf(active), msg: greet(active[0].name)}

Field Access

Copypayload.name               // dot access
payload["first name"]      // bracket key
payload."first name"       // dot + quoted key
payload?.address?.city     // safe navigation (null if missing)
payload.users[0]           // 0-based index
payload.users[-1]          // last element
payload.users[0 to 2]      // range slice
payload.card[-4 to -1]     // last 4 chars of a string
payload.users[*].name      // wildcard: all names
payload..name              // descendants: all name values at any depth
xml.employee.@id           // XML attribute access (@ prefix)
xml.employee.@id           // Stored as "@id" key in parsed XML map

Operators

Arithmetic & Concatenation

Comparison & Logical

Object shorthand New

Copy// IDENTIFIER: expr  creates {IDENTIFIER: expr}
result: payload.users filter $.active
// same as: {result: payload.users filter $.active}

filter

Copypayload filter $.age > 25
payload filter ((item, index) -> item.active and index > 0)
payload filter isEven($)

map

Copypayload map $.name
payload map ($ * 2)
payload map (value, index) -> {id: index, v: value}
payload map (v,k) -> {num: v.num last 3}

reduce

Copypayload reduce ($$ + $)
payload reduce ((item, acc = 0) -> acc + item)
payload reduce ((item, acc = {}) -> acc ++ {(item.name): item.value})

groupBy

Copypayload groupBy $.dept
(payload groupBy $.dept) mapObject (members, dept) ->
  {(dept): members map $.name}

mapObject

$ = value, $$ = key, $$$ = index

Copypayload mapObject (value, key) -> {(key): upper(value)}
payload mapObject {(upper($$)): $}
payload mapObject (v, k, i) -> {(i): {key: k, val: v}}  // $$$ = index

filterObject

Copypayload filterObject ($ != null)
payload filterObject ((value, key) -> key != "password")
payload filterObject ((v, k, i) -> k ~= "id")      // ~= type-coercing equal

let / fun Enhanced

Copy// var in header (preferred)
output application/json
var active = payload.users filter $.active
var total  = sizeOf(active)
---
{total: total, users: active}

// fun with typed params + default + --- separator
fun factorial(n:Number, acc:Number=1) =
  (if (n <= 1) acc else factorial(n-1, acc*n))
---
factorial(payload)

if / else / match

Copyif (payload.status == "OK") 200 else 500
payload.score > 90 ? "A" : "B"

payload match {
  case "A"         -> 1
  case s is String -> upper(s)
  case n is Number -> n * 2
  else             -> null
}

Lambdas

Copy$ -> $ * 2
(x) -> x * 2
(value, index) -> {id: index, v: value}
(item, acc = 0) -> acc + item

String Functions

String interpolation

Copy"Hello, $(payload.name)! Age: $(payload.age)"

Array Functions

Object Functions

Math Functions

Type & Logic Functions

Crypto Functions New

Cryptographic hashing, HMAC, and symmetric encryption via dw::Crypto-compatible built-ins.

Copy// Hashing
MD5("hello")                        // "5d41402abc4b2a76b9719d911017c592"
SHA256("hello")                     // "2cf24dba5fb0a30e..."

// HMAC
HMACWith("payload", "secret", "HmacSHA256")

// AES-256-GCM round-trip
let cipher = aesEncrypt("hello world", "mySecretKey")
aesDecrypt(cipher, "mySecretKey")   // "hello world"

Tree Functions New

Recursive tree traversal helpers from dw::util::Tree.

Copy// Uppercase every string leaf
mapLeafValues({a: "hello", b: {c: "world"}}, (v) -> upper(v))
// {a: "HELLO", b: {c: "WORLD"}}

// Remove empty fields at any depth
filterTree(payload, (v, path) -> !isEmpty(v as String))

Date & Time Functions

Pattern: Data Transformation

Copy{fullName: payload.name, userAge: payload.age}
payload ++ {tax: payload.price * 0.1}
payload - "password" - "token"
(payload filter $.active) map $.email

Pattern: Dynamic Keys

Copy{(payload.key): payload.value}
payload map (value, index) -> {("item" ++ index): value}
(payload groupBy $.customer)
  mapObject (orders, cust) -> {(cust): sizeOf(orders)}

Pattern: Nested Maps

Copyflatten(payload.customers map (cus) ->
  (cus.orders map {customer: cus.name, orderId: $.id}))

Pattern: Merge & Join

Copy(payload.arr1 ++ payload.arr2) distinctBy $
payload reduce ($$ ++ $)
payload.metrics reduce ((item, acc={}) ->
  acc ++ {(item.name): item.value})

Pattern: Recursion

Copyfun factorial(n:Number, acc:Number=1) =
  (if (n <= 1) acc else factorial(n-1, acc*n))
---
factorial(payload)     // factorial(6) -> 720

fun recsum(arr, total=0) =
  if (isEmpty(arr)) total
  else recsum(arr[1 to -1], total + arr[0])
---
recsum(1 to 10)        // -> 55

Keyboard Shortcuts

REST API Reference

CopyPOST /api/v1/transform
{
  "dsl":       "output application/json\n---\npayload filter $.age > 25",
  "json":      "<employees><employee id=\"1\"><name>Alice</name></employee></employees>",
  "inputType": "XML",        // JSON (default) | XML | CSV | YAML | TEXT
  "pretty":    true,
  "variables": {"cfg": {"content":"{\"env\":\"prod\"}","type":"JSON"}}
}

Enterprise Features