Fix guarded expressions being utilized elsewhere (#179)

+ (Close #171) + (close #174) + (close #176)
babel · Oct 5, 2016 · 11664eb · 11664eb
1 parent 23aec22
commit 11664eb
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Showing 2 changed files with 13 additions and 3 deletions.
diff --git a/packages/babel-plugin-minify-guarded-expressions/__tests__/guarded-expressions-test.js b/packages/babel-plugin-minify-guarded-expressions/__tests__/guarded-expressions-test.js
@@ -76,7 +76,7 @@ describe("guarded-expressions-plugin", () => {
       alert(new Foo() || false);
     `);
     expected = unpad(`
-      alert(new Foo());
+      alert(new Foo() || false);
     `);
     expect(transform(source)).toBe(expected);
   });

diff --git a/packages/babel-plugin-minify-guarded-expressions/src/index.js b/packages/babel-plugin-minify-guarded-expressions/src/index.js
@@ -17,14 +17,24 @@ module.exports = function({ types: t }) {
 
             const left = path.get("left");
             const right = path.get("right");
+
+            // issues - 171, 174, 176
+            // we assume that it is returned/assigned/part of a bigger expression
+            // or utilized somehow
+            // we check if we shouldBail only when evaluating
+            // the rightside of the expression;
+            // if the left side is evaluated to be deterministic,
+            // we can safely replace the entire expression
+            const shouldBail = !path.parentPath.isExpressionStatement();
+
             if (node.operator === "&&") {
               const leftTruthy = left.evaluateTruthy();
               if (leftTruthy === false) {
                 // Short-circuit
                 path.replaceWith(node.left);
               } else if (leftTruthy === true && left.isPure()) {
                 path.replaceWith(node.right);
-              } else if (right.evaluateTruthy() === false && right.isPure()) {
+              } else if (right.evaluateTruthy() === false && right.isPure() && !shouldBail) {
                 path.replaceWith(node.left);
               }
             } else if (node.operator === "||") {
@@ -34,7 +44,7 @@ module.exports = function({ types: t }) {
               } else if (leftTruthy === true) {
                 // Short-circuit
                 path.replaceWith(node.left);
-              } else if (right.evaluateTruthy() === false && right.isPure()) {
+              } else if (right.evaluateTruthy() === false && right.isPure() && !shouldBail) {
                 path.replaceWith(node.left);
               }
             }