diff --git a/packages/babel-traverse/src/path/family.js b/packages/babel-traverse/src/path/family.js
index f1fe88dd54..f466cb1bd6 100644
--- a/packages/babel-traverse/src/path/family.js
+++ b/packages/babel-traverse/src/path/family.js
@@ -22,7 +22,7 @@ export function getStatementParent(): ?NodePath {
   return path;
 }
 
-export function getOpposite() {
+export function getOpposite() : ?NodePath {
   if (this.key === "left") {
     return this.getSibling("right");
   } else if (this.key === "right") {
@@ -148,11 +148,11 @@ export function _getPattern(parts, context) {
   return path;
 }
 
-export function getBindingIdentifiers(duplicates?) {
+export function getBindingIdentifiers(duplicates?): Object {
   return t.getBindingIdentifiers(this.node, duplicates);
 }
 
-export function getOuterBindingIdentifiers(duplicates?) {
+export function getOuterBindingIdentifiers(duplicates?): Object {
   return t.getOuterBindingIdentifiers(this.node, duplicates);
 }