feat: add isValidScriptlet api

Author: DylanPiercey

.changeset/afraid-radios-begin.md

@@ -0,0 +1,5 @@
+---
+"htmljs-parser": minor
+---
+
+Add "isValidScriptlet" api.

src/__tests__/validate.test.ts

@@ -1,5 +1,6 @@
 import assert from "node:assert/strict";
 import { isValidAttrValue, isValidStatement } from "..";
+import { isValidScriptlet } from "../util/validators";
 
 describe("validation helpers", () => {
   describe("isValidStatement", () => {
@@ -28,6 +29,32 @@ describe("validation helpers", () => {
     });
   });
 
+  describe("isValidScriptlet", () => {
+    it("accepts single-line expressions", () => {
+      assert.equal(isValidScriptlet("foo + bar"), 2);
+    });
+
+    it("rejects indented continuation lines", () => {
+      assert.equal(isValidScriptlet("foo\n  + bar"), 0);
+    });
+
+    it("rejects unindented continuation lines", () => {
+      assert.equal(isValidScriptlet("foo\nbar"), 0);
+    });
+
+    it("accepts indented ternary continuation", () => {
+      assert.equal(isValidScriptlet("foo ?\n  bar : baz"), 2);
+    });
+
+    it("rejects unterminated groups", () => {
+      assert.equal(isValidScriptlet("(foo"), 0);
+    });
+
+    it("rejects mismatched closing groups", () => {
+      assert.equal(isValidScriptlet(")"), 0);
+    });
+  });
+
   describe("isValidAttrValue", () => {
     it("accepts html attr values with operators", () => {
       assert.equal(isValidAttrValue("foo + bar", false), 2);

src/util/validators.ts

@@ -44,6 +44,15 @@ function prepareStatement(expr: STATE.ExpressionMeta) {
   expr.consumeIndentedContent = true;
 }
 
+export function isValidScriptlet(code: string): Validity {
+  return isValid(code, true, prepareScriptlet);
+}
+
+function prepareScriptlet(expr: STATE.ExpressionMeta) {
+  expr.operators = true;
+  expr.terminatedByEOL = true;
+}
+
 export function isValidAttrValue(code: string, concise: boolean): Validity {
   return isValid(code, concise, prepareAttrValue);
 }