fix: handle undefined exports (#24)

* handle undefined exports * add test to handle undefined exports
kentcdodds · Jul 19, 2017 · 34779bd · 34779bd
2 parents 4d5ba72 + e123d02
commit 34779bd
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diff --git a/src/__tests__/__snapshots__/index.js.snap b/src/__tests__/__snapshots__/index.js.snap
@@ -369,3 +369,16 @@ module.exports = fib(10)
 module.exports = 55;
 
 `;
+
+exports[`34. preval 1`] = `
+
+// @preval
+let smth = {}
+module.exports = smth.UNDEFINED;
+
+      ↓ ↓ ↓ ↓ ↓ ↓
+
+// this file was prevaled
+module.exports = undefined;
+
+`;
diff --git a/src/__tests__/index.js b/src/__tests__/index.js
@@ -203,6 +203,13 @@ pluginTester({
         import x from "./fixtures/compute-one.js";
       `,
     },
+    {
+      code: `
+        // @preval
+        let smth = {}
+        module.exports = smth.UNDEFINED;
+      `,
+    },
 
     // please add a file for your use-case
     // in the `fixtures` directory and make

diff --git a/src/object-to-ast.js b/src/object-to-ast.js
@@ -9,7 +9,11 @@ function objectToAST(object) {
 }
 
 function stringify(object) {
-  return JSON.stringify(object, stringifyReplacer).replace(
+  let str = JSON.stringify(object, stringifyReplacer)
+  if (str === undefined) {
+    str = 'undefined'
+  }
+  return str.replace(
     /"__FUNCTION_START__(.*?)__FUNCTION_END__"/g,
     functionReplacer,
   )