fix negative number bug

william-yz · Apr 29, 2019 · 7774faf · 7774faf
1 parent 6b1f755
commit 7774faf
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Showing 3 changed files with 6 additions and 3 deletions.
diff --git a/__tests__/evaluate.spec.ts b/__tests__/evaluate.spec.ts
@@ -44,6 +44,7 @@ describe('evaluate expression', () => {
   it('== & !=', () => {
     expect(evaluate('1 == 1')).toEqual(true);
     expect(evaluate('2 == 1')).toEqual(false);
+    expect(evaluate('1 != -1')).toEqual(true);
     expect(evaluate('1 == "1"')).toEqual(true);
     expect(evaluate('1 != 1')).toEqual(false);
     expect(evaluate('2 != 1')).toEqual(true);

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ts-expression-evaluator",
-  "version": "1.3.12",
+  "version": "1.3.13",
   "description": "Context-based expression parse and evaluator.",
   "main": "build/main/index.js",
   "typings": "build/main/index.d.ts",
@@ -99,4 +99,4 @@
       }
     }
   }
-}
+}
diff --git a/src/lib/Handlers.ts b/src/lib/Handlers.ts
@@ -73,11 +73,13 @@ export const Handlers: Handlers = {
     throw new Error();
   },
 
-  UnaryExpression(ast: t.Expression, context: Context): boolean {
+  UnaryExpression(ast: t.Expression, context: Context): boolean | number {
     if (t.isUnaryExpression(ast)) {
       switch (ast.operator) {
         case '!':
           return !evaluate(ast.argument, context);
+        case '-':
+          return - evaluate(ast.argument, context);
       }
     }
     throw new Error();