Support actions with constants (#16)

* Add support for actions that reference constants

* Add test with an action that references a constant

---------

Signed-off-by: Reece Dunham <me@rdil.rocks>
Co-authored-by: Reece Dunham <me@rdil.rocks>

Author: grappigegovert

src/handleEvent.ts

@@ -156,10 +156,10 @@ export function handleEvent<Context = unknown, Event = unknown>(
                         },
                         {
                             ...newContext,
+                            ...(definition.Constants || {}),
                             ...(options.contractId && {
                                 ContractId: options.contractId,
                             }),
-                            ...(definition.Constants || {}),
                             Value: event,
                         },
                         {

tests/handleEvent.data.json

@@ -117,6 +117,29 @@
             }
         }
     },
+    "actionWithConstants": {
+        "Definition": {
+            "Context": {
+                "Variable": 0
+            },
+            "Constants": {
+                "ValueToAdd": 500
+            },
+            "States": {
+                "Start": {
+                    "Event": {
+                        "Actions": {
+                            "$inc": ["Variable", "$.ValueToAdd"]
+                        }
+                    }
+                }
+            }
+        },
+        "Input": {
+            "Name": "Event",
+            "Value": {}
+        }
+    },
     "pushUniqueAsCondition": {
         "Definition": {
             "Context": {

tests/handleEvent.spec.ts

@@ -96,7 +96,7 @@ describe("handleEvent api", () => {
         assert.strictEqual(result.state, "Success", "Transition did not happen")
     })
 
-    it("works with constants", () => {
+    it("supports tests with constants", () => {
         const { Definition, Input } = suites.testWithConstants
 
         let state = "Start"
@@ -115,6 +115,25 @@ describe("handleEvent api", () => {
         assert.strictEqual(result.state, "Success", "Transition did not happen")
     })
 
+    it("supports actions with constants", () => {
+        const { Definition, Input } = suites.actionWithConstants
+
+        let state = "Start"
+
+        const result = handleEvent(
+            Definition,
+            Definition.Context,
+            Input.Value,
+            {
+                currentState: state,
+                eventName: Input.Name,
+                timestamp: 0,
+            }
+        )
+
+        assert.strictEqual(result.context["Variable"], 500)
+    })
+
     it("supports pushunique", () => {
         const { Definition, Input } = suites.pushUniqueAsCondition
         let context: Required<typeof Definition.Context> = Definition.Context