fix(percentage): handle decimal points

Author: sudkumar

src/index.test.ts

@@ -17,13 +17,16 @@ describe("Evaluate Numerical Expressions", () => {
 
   it("Handle % for tax", () => {
     expect(evalNumExpr("10+18%")).toBe(11.8);
+    expect(evalNumExpr("10+18.0%")).toBe(11.8);
+    expect(evalNumExpr("10-18.0%")).toBe(8.2);
     expect(evalNumExpr("10+10+18%")).toBe(23.6);
     expect(evalNumExpr("100+(10+10+18%)")).toBe(123.6);
     expect(evalNumExpr("175 + 40 + 18%")).toBe(253.7);
   });
   it("Handle % for percentage", () => {
     expect(evalNumExpr("2*5+6%2")).toBe(10.12); // 2 * 5 + 6/100 * 2
     expect(evalNumExpr("10*6%")).toBe(0.6);
+    expect(evalNumExpr("20+20%%")).toBe(20.002);
     expect(evalNumExpr("10 + 10*5%")).toBe(10.5);
     expect(evalNumExpr("10 + (100 - 100 * 18%) * 5 + 40 / 20")).toBe(422);
   });

src/index.ts

@@ -193,8 +193,8 @@ function tokenize(
     .replace(/\s/gi, "") // replace all spaces
     .replace(/[xX]/gi, "*") // replace the x with multiplier *
     .replace(/[^+-/*^\d().%]/g, "")
-    .replace(/\+(\d+)%(?![*/(\d])/gi, "add_percentage$1")
-    .replace(/-(\d+)%(?![*/(\d])/gi, "sub_percentage$1")
+    .replace(/\+([\d.]+)%(?![*/%(\d])/gi, "add_percentage$1")
+    .replace(/-([\d.]+)%(?![*/%(\d])/gi, "sub_percentage$1")
     .replace(/%([\d(])/gi, "/100*$1")
     .replace(/%/gi, "/100")
     // i have no idea why commas were not replaced :(