From 0524629cb766eb72b0d18a13c3512c860a3b5ac6 Mon Sep 17 00:00:00 2001
From: Christopher Pardy <chris@rategravity.com>
Date: Thu, 26 Jul 2018 15:30:34 -0400
Subject: [PATCH] Treat missing fields as undefined \n* Add test to ensure a
 missing required field is an error* Add test to ensure undefined is allowed
 for undefined fields* Add test to ensure that missing fields are treated as
 undefined.

---
 src/index.spec.ts   | 17 ++++++++++++++++-
 src/types/record.ts | 12 +++++-------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/index.spec.ts b/src/index.spec.ts
index f3172e10..5df9d4c8 100644
--- a/src/index.spec.ts
+++ b/src/index.spec.ts
@@ -87,6 +87,7 @@ const runtypes = {
   InstanceOfSomeClass: InstanceOf(SomeClass),
   InstanceOfSomeOtherClass: InstanceOf(SomeOtherClass),
   DictionaryOfArraysOfSomeClass: Dictionary(Array(InstanceOf(SomeClass))),
+  OptionalKey: Record({ foo: String, bar: Union(Number, Undefined) }),
 };
 
 type RuntypeName = keyof typeof runtypes;
@@ -111,7 +112,7 @@ const testValues: { value: always; passes: RuntypeName[] }[] = [
   { value: { Boolean: true, Number: 3 }, passes: ['record1', 'union1', 'Partial'] },
   { value: { Boolean: true }, passes: ['Partial'] },
   { value: { Boolean: true, foo: undefined }, passes: ['Partial'] },
-  { value: { Boolean: true, foo: 'hello' }, passes: ['Partial'] },
+  { value: { Boolean: true, foo: 'hello' }, passes: ['Partial', 'OptionalKey'] },
   { value: { Boolean: true, foo: 5 }, passes: [] },
   { value: (x: number, y: string) => x + y.length, passes: ['Function'] },
   { value: { name: undefined, likes: [] }, passes: [] },
@@ -130,6 +131,8 @@ const testValues: { value: always; passes: RuntypeName[] }[] = [
   { value: [1, 2, 3, 4], passes: ['ArrayNumber', 'CustomArray', 'CustomArrayWithMessage'] },
   { value: new SomeClass(42), passes: ['InstanceOfSomeClass'] },
   { value: { xxx: [new SomeClass(55)] }, passes: ['DictionaryOfArraysOfSomeClass'] },
+  { value: { foo: 'hello' }, passes: ['OptionalKey', 'Dictionary'] },
+  { value: { foo: 'hello', bar: undefined }, passes: ['OptionalKey'] },
 ];
 
 for (const { value, passes } of testValues) {
@@ -297,6 +300,18 @@ describe('check errors', () => {
     );
   });
 
+  it('record missing keys', () => {
+    assertThrows(
+      { name: 'Jack' },
+      Record({
+        name: String,
+        age: Number,
+      }),
+      'Expected number, but was undefined',
+      'age',
+    );
+  });
+
   it('record complex', () => {
     assertThrows(
       { name: 'Jack', age: 10, likes: [{ title: false }] },
diff --git a/src/types/record.ts b/src/types/record.ts
index 463a9f2e..bab07fca 100644
--- a/src/types/record.ts
+++ b/src/types/record.ts
@@ -21,13 +21,11 @@ export function Record<O extends { [_: string]: Runtype }>(fields: O) {
 
       // tslint:disable-next-line:forin
       for (const key in fields) {
-        if (hasKey(key, x)) {
-          try {
-            fields[key].check(x[key]);
-          } catch ({ key: nestedKey, message }) {
-            throw validationError(message, nestedKey ? `${key}.${nestedKey}` : key);
-          }
-        } else throw validationError(`Expected ${key} to be ${show(fields[key].reflect)}`, key);
+        try {
+          fields[key].check(hasKey(key, x) ? x[key] : undefined);
+        } catch ({ key: nestedKey, message }) {
+          throw validationError(message, nestedKey ? `${key}.${nestedKey}` : key);
+        }
       }
 
       return x as O;