Auto call functions in kabel; clean up end behavior of worklet; move kabel first in chain; write docstring

packages/transpiler/test/transpiler.test.mjs

@@ -32,6 +32,11 @@ describe('transpiler', () => {
   it('treats K(...) as kabelsalat', () => {
     expect(transpiler('K(1+2)', simple).output).toEqual("worklet('1 + 2');");
   });
+  it('automatically calls functions in K(...)', () => {
+    expect(transpiler('K(() => { return 1 + 2 })', simple).output).toEqual(
+      "worklet('(() => {\\n    return 1 + 2\\n})()');",
+    );
+  });
   it('handles strudel S(...) inside kabelsalat K(...)', () => {
     expect(transpiler('K(S("bd".fast(4)))', simple).output).toEqual("worklet('pat[0]', m('bd', 4).fast(4));");
   });

packages/transpiler/transpiler.mjs

@@ -123,9 +123,18 @@ export function transpiler(input, options = {}) {
     leave(node, parent, prop, index) {
       if (!isKabelCall(node)) return;
 
-      const [expr, ...rest] = node.arguments;
+      let [expr, ...rest] = node.arguments;
       if (!expr) throw new Error('K(...) requires an expression');
 
+      if (shouldCallKabelExpression(expr)) {
+        expr = {
+          type: 'CallExpression',
+          callee: expr,
+          arguments: [],
+          optional: false,
+        };
+      }
+
       const { template, patternExprs } = extractPatternPlaceholders(expr);
       if (patternExprs.length) {
         const workletArgs = [{ type: 'Literal', value: template }, ...patternExprs, ...rest];
@@ -211,6 +220,16 @@ function isKabelCall(node) {
   return callee.type === 'Identifier' && callee.name === 'K';
 }
 
+function shouldCallKabelExpression(expr) {
+  if (expr.type !== 'ArrowFunctionExpression' && expr.type !== 'FunctionExpression') {
+    return false;
+  }
+  if (expr.params.length) {
+    return false;
+  }
+  return expr.body?.type === 'BlockStatement';
+}
+
 function genExprSource(expr) {
   return escodegen.generate(expr, { format: { semicolons: false } });
 }