release: WRNexusJS 0.2.31

packages/compiler/src/parser.ts

@@ -105,6 +105,19 @@ export interface ModeFunctionsBlock {
   body: string;
 }
 
+export type LifecycleHookName = "mount" | "update" | "unmount";
+
+export interface LifecycleBlock {
+  mount?: string;
+  update?: string;
+  unmount?: string;
+}
+
+export interface WatchBlock {
+  state: string;
+  body: string;
+}
+
 export interface RealtimeHandler {
   event: string;
   args: string[];
@@ -141,6 +154,8 @@ export interface PageAst {
   functions: string[];
   dataApis: DataApiBlock[];
   modeFunctions: ModeFunctionsBlock[];
+  lifecycle: LifecycleBlock;
+  watches: WatchBlock[];
   apis: ApiBlock[];
   realtimes: RealtimeBlock[];
 }
@@ -210,6 +225,8 @@ export function parse(source: string): PageAst {
     const functions: string[] = [];
     const dataApis: DataApiBlock[] = [];
     const modeFunctions: ModeFunctionsBlock[] = [];
+    const lifecycle: LifecycleBlock = {};
+    const watches: WatchBlock[] = [];
     const apis: ApiBlock[] = [];
     const realtimes: RealtimeBlock[] = [];
 
@@ -339,6 +356,52 @@ export function parse(source: string): PageAst {
           styles.push(lx.readBalancedBraces());
           break;
         }
+        case "lifecycle": {
+          lx.next();
+          expect("lbrace");
+
+          while (lx.peek().type !== "rbrace") {
+            const hook = lx.peek();
+
+            if (hook.type === "eof") {
+              throw new ParseError("Unexpected end of input inside lifecycle block");
+            }
+
+            if (hook.type !== "ident") {
+              throw new ParseError(`Expected a lifecycle hook at offset ${hook.pos}`);
+            }
+
+            if (hook.value !== "mount" && hook.value !== "update" && hook.value !== "unmount") {
+              throw new ParseError(`Unknown lifecycle hook '${hook.value}' at offset ${hook.pos}`);
+            }
+
+            const hookName = hook.value as LifecycleHookName;
+
+            lx.next();
+
+            if (lifecycle[hookName] !== undefined) {
+              throw new ParseError(`Duplicate lifecycle hook '${hookName}' at offset ${hook.pos}`);
+            }
+
+            lifecycle[hookName] = lx.readBalancedBraces();
+          }
+
+          expect("rbrace");
+          break;
+        }
+        case "watch": {
+          lx.next();
+
+          const stateName = expect("ident").value;
+          const body = lx.readBalancedBraces();
+
+          watches.push({
+            state: stateName,
+            body,
+          });
+
+          break;
+        }
         case "functions": {
           lx.next();
           functions.push(lx.readBalancedBraces());
@@ -350,6 +413,14 @@ export function parse(source: string): PageAst {
     }
     expect("rbrace");
 
+    const declaredStates = new Set(states.map((state) => state.name));
+
+    for (const watcher of watches) {
+      if (!declaredStates.has(watcher.state)) {
+        throw new ParseError(`Cannot watch undeclared state '${watcher.state}'`);
+      }
+    }
+
     return {
       type: "page",
       kind,
@@ -363,6 +434,8 @@ export function parse(source: string): PageAst {
       functions,
       dataApis,
       modeFunctions,
+      lifecycle,
+      watches,
       apis,
       realtimes,
     };