diff --git a/src/__tests__/abuse.test.js b/src/__tests__/abuse.test.js
index f2bb0dc..9300e80 100644
--- a/src/__tests__/abuse.test.js
+++ b/src/__tests__/abuse.test.js
@@ -36,7 +36,7 @@ describe('Provides descriptive error messages for API abuse', () => {
       // $FlowExpectError
       idLoader.load();
     }).toThrow(
-      'The loader.load() function must be called with a value,' +
+      'The loader.load() function must be called with a value, ' +
       'but got: undefined.'
     );
 
@@ -44,7 +44,7 @@ describe('Provides descriptive error messages for API abuse', () => {
       // $FlowExpectError
       idLoader.load(null);
     }).toThrow(
-      'The loader.load() function must be called with a value,' +
+      'The loader.load() function must be called with a value, ' +
       'but got: null.'
     );
 
diff --git a/src/index.js b/src/index.js
index f5f4e15..6250df9 100644
--- a/src/index.js
+++ b/src/index.js
@@ -74,7 +74,7 @@ class DataLoader<K, V, C = K> {
   load(key: K): Promise<V> {
     if (key === null || key === undefined) {
       throw new TypeError(
-        'The loader.load() function must be called with a value,' +
+        'The loader.load() function must be called with a value, ' +
         `but got: ${String(key)}.`
       );
     }