Merge pull request #13 from codemodsquad/fix/remove-final-return-undefined

fix(cleanup): return and re-await issues

Author: jedwards1211

src/util/finalCleanup.ts

@@ -60,6 +60,22 @@ export default function finalCleanup(path: NodePath<t.Function>): void {
           } else if (value) {
             argument.replaceWith(isInTryBlock(path) ? awaited(value) : value)
           }
+        } else if (argument.isIdentifier()) {
+          const binding = path.scope.getBinding(argument.node.name)
+          if (
+            binding &&
+            binding.constant &&
+            binding.path.isVariableDeclarator() &&
+            (binding.path as NodePath<t.VariableDeclarator>)
+              .get('init')
+              .isAwaitExpression()
+          ) {
+            if (parentPath.isExpressionStatement()) {
+              path.remove()
+            } else {
+              path.replaceWith(argument.node)
+            }
+          }
         }
       },
       ReturnStatement(path: NodePath<t.ReturnStatement>) {

test/fixtures/bugs_PostgresConnectionManager.connect.ts

@@ -271,9 +271,9 @@ class ConnectionManager {
 
     if (query) {
       await connection1.query(query);
-      connection0 = await connection1;
+      connection0 = connection1;
     } else {
-      connection0 = await connection1;
+      connection0 = connection1;
     }
     if (Object.keys(this.nameOidMap).length === 0 &&
       this.enumOids.oids.length === 0 &&

test/fixtures/bugs_Sequelize.transaction.ts

@@ -50,7 +50,7 @@ class Sequelize {
         await transaction.prepareEnvironment();
         const result = await autoCallback(transaction);
         await transaction.commit();
-        return await result;
+        return result;
       } catch (err) {
         // Rollback transaction if not already finished (commit, rollback, etc)
         // and reject with original error (ignore any error in rollback)

test/fixtures/conditionalReturnCatch_AssignedToIdentifier.ts

@@ -37,7 +37,7 @@ async function createUser(args) {
       user0 = await addUserToGroups(user1, groups)
     } else {
       console.log('blah')
-      user0 = await user1
+      user0 = user1
     }
     if (groups) {
       console.log('test')

test/fixtures/conditionalReturnCatch_ElseFallsThrough.ts

@@ -43,7 +43,7 @@ async function createUser(args) {
       user = await addUserToGroups(user0, groups)
     } else {
       console.log('d')
-      user = await user0
+      user = user0
     }
   } catch (err) {
     console.error(err.stack)

test/fixtures/conditionalReturnCatch_FirstConsequentFallsThrough.ts

@@ -31,7 +31,7 @@ async function createUser(args) {
     const user0 = await Users.create({ username })
     if (groups) {
       console.log('a')
-      user = await user0
+      user = user0
     } else if (foo) {
       console.log('b')
       user = await addUserToGroups(user0, groups)

test/fixtures/conditionalReturnCatch_MissingElseFallsThrough.ts

@@ -42,7 +42,7 @@ async function createUser(args) {
       user = await addUserToGroups(user0, groups)
     } else {
       console.log('d')
-      user = await user0
+      user = user0
     }
   } catch (err) {
     console.error(err.stack)

test/fixtures/conditionalReturnCatch_Returned.ts

@@ -25,7 +25,7 @@ async function createUser(args) {
     if (groups) {
       return await addUserToGroups(user, groups)
     }
-    return await user
+    return user
   } catch (err) {
     console.error(err.stack)
     return dummyUser()

test/fixtures/conditionalReturnCatch_SecondConsequentFallsThrough.ts

@@ -34,7 +34,7 @@ async function createUser(args) {
       user = await addUserToGroups(user0, groups)
     } else if (foo) {
       console.log('b')
-      user = await user0
+      user = user0
     } else {
       console.log('c')
       user = await addUserToGroups(user0, groups)

test/fixtures/finalReturnUndefined.ts

@@ -0,0 +1,21 @@
+export const input = `
+async function foo() {
+  await bar.then(baz => {
+    if (qux) {
+      return qux.then(() => baz)
+    }
+    return baz
+  })
+}
+`
+
+export const options = {}
+
+export const expected = `
+async function foo() {
+  const baz = await bar
+  if (qux) {
+    await qux
+  }
+}
+`