Code frameworks
Recipe: spend a resource
Write an action that does nothing when a resource is gone, and test both cases.
Goal
Let a Keeper strike three sparks. A fourth does nothing.
The change
rules/spark.ts
export function spark(self: ElementRef): void {
const charges: number = element.var(self, "charges") as number;
if (charges > 0) {
ledger.add(self, "charges", -1);
}
}- Line 2 Read the resource.
- Lines 3-5 Spend one only while some is left. Otherwise the action writes nothing.
Declare the action in the schema.
schemas/keeper.json
"actions": [
{ "id": "hurt", "name": "Take damage", "source": "rules/hurt.ts" },
{ "id": "heal", "name": "Heal", "source": "rules/heal.ts" },
{ "id": "spark", "name": "Strike a spark", "source": "rules/spark.ts" }
],- Line 13 The new action.
The constructor returns charges with a starting value of 3.
rules/keeper.ts
export function construct(
name: string,
max_hp: number,
): { name: string; max_hp: number; hp: number; charges: number } {
return { name: name, max_hp: max_hp, hp: max_hp, charges: 3 };
}- Lines 5-6 charges is a stored field with a starting value of 3.
Add an alias for the action to the Frame's dataContract and a button that uses it, or players cannot use it from the sheet.
layouts/keeper.json
{ "name": "spark", "functionRef": "spark" }- Line 20 The alias for the action.
layouts/keeper.json
{ "kind": "button", "label": "Strike a spark", "actionRef": "spark" }- Line 34 The button that calls it.
Test it
scenarios/spark.json
{
"id": "spend-all-charges",
"framework": "keeper",
"parameters": { "name": "Mira", "max_hp": 10 },
"expectedValues": { "name": "Mira", "max_hp": 10, "hp": 10, "charges": 3 },
"actions": [
{
"action": "spark",
"parameters": {},
"expectedWrites": [
{ "op": "ledger.add", "key": "charges", "value": -1 }
]
},
{
"action": "spark",
"parameters": {},
"expectedWrites": [
{ "op": "ledger.add", "key": "charges", "value": -1 }
]
},
{
"action": "spark",
"parameters": {},
"expectedWrites": [
{ "op": "ledger.add", "key": "charges", "value": -1 }
]
},
{ "action": "spark", "parameters": {}, "expectedWrites": [] }
]
}- Lines 7-27 Three sparks each spend one charge.
- Line 28 The fourth finds no charges, so it expects no writes.
manifest/project.json
{
"formatVersion": "fabled.game-project/v1",
"projectId": "game-your-game-id",
"projectKind": "GAME",
"compilerProfile": "native-game-v1",
"name": "Lantern Keepers",
"entryFramework": "keeper",
"frameworks": ["schemas/keeper.json"],
"scenarios": [
"scenarios/new-keeper.json",
"scenarios/heal.json",
"scenarios/spark.json"
]
}- Line 12 The new scenario file.
List the new scenario file in the manifest. Add charges to the expected values of the other two scenarios.