feat(eval): compiled and cached expressions

packages/bruno-js/tests/utils.spec.js

@@ -0,0 +1,68 @@
+const { evaluateJsExpression, internalExpressionCache: cache } = require("../src/utils");
+
+describe("utils", () => {
+  describe("expression evaluation", () => {
+    const context = {
+      res: {
+        data: { pets: ["bruno", "max"] }
+      }
+    };
+
+    afterEach(() => cache.clear());
+
+    it("should evaluate expression", () => {
+      let result;
+
+      result = evaluateJsExpression("res.data.pets", context);
+      expect(result).toEqual(["bruno", "max"]);
+
+      result = evaluateJsExpression("res.data.pets[0].toUpperCase()", context);
+      expect(result).toEqual("BRUNO");
+    });
+
+    it("should cache expression", () => {
+      expect(cache.size).toBe(0);
+      evaluateJsExpression("res.data.pets", context);
+      expect(cache.size).toBe(1);
+    });
+
+    it("should identify top level variables", () => {
+      const expr = "res.data.pets[0].toUpperCase()";
+      evaluateJsExpression(expr, context);
+      expect(cache.get(expr).toString()).toContain("const { res } = context;");
+    });
+
+    it("should not duplicate variables", () => {
+      const expr = "res.data.pets[0] + res.data.pets[1]";
+      evaluateJsExpression(expr, context);
+      expect(cache.get(expr).toString()).toContain("const { res } = context;");
+    });
+
+    it("should exclude js keywords like true false from vars", () => {
+      const expr = "res.data.pets.length > 0 ? true : false";
+      evaluateJsExpression(expr, context);
+      expect(cache.get(expr).toString()).toContain("const { res } = context;");
+    });
+
+    it("should exclude numbers from vars", () => {
+      const expr = "res.data.pets.length + 10";
+      evaluateJsExpression(expr, context);
+      expect(cache.get(expr).toString()).toContain("const { res } = context;");
+    });
+
+    it("should pick variables from complex expressions", () => {
+      const expr = "res.data.pets.map(pet => pet.length)";
+      const result = evaluateJsExpression(expr, context);
+      expect(result).toEqual([5, 3]);
+      expect(cache.get(expr).toString()).toContain("const { res, pet } = context;");
+    });
+
+    it("should be ok picking extra vars from strings", () => {
+      const expr = "'hello' + ' ' + res.data.pets[0]";
+      const result = evaluateJsExpression(expr, context);
+      expect(result).toBe("hello bruno");
+      // extra var hello is harmless
+      expect(cache.get(expr).toString()).toContain("const { hello, res } = context;");
+    });
+  });
+});