fix: passing null object to type array defaults to empty array (#249) (#265)

* fix: passing null object to type array defaults to empty array (#249)

* test: added test with default field in schema

* test: removed redundant test

* fix: now we throw an error with a clear message if receiving a null on array type

Author: alemagio

index.js

@@ -937,7 +937,7 @@ function buildObject (location, code, name) {
   return code
 }
 
-function buildArray (location, code, name) {
+function buildArray (location, code, name, key = null) {
   var schema = location.schema
   code += `
     function ${name} (obj) {
@@ -988,6 +988,14 @@ function buildArray (location, code, name) {
     result = nested(laterCode, name, '[i]', mergeLocation(location, { schema: schema.items }), undefined, true)
   }
 
+  if (key) {
+    code += `
+    if(!Array.isArray(obj)) {
+      throw new TypeError(\`Property '${key}' should be of type array, received '$\{obj}' instead.\`)
+    }
+    `
+  }
+
   code += `
     var l = obj.length
     var w = l - 1
@@ -1131,7 +1139,7 @@ function nested (laterCode, name, key, location, subKey, isArray) {
       break
     case 'array':
       funcName = asFuncName('$arr' + name + key + subKey) // eslint-disable-line
-      laterCode = buildArray(location, laterCode, funcName)
+      laterCode = buildArray(location, laterCode, funcName, key)
       code += `
         json += ${funcName}(obj${accessor})
       `

test/typesArray.test.js

@@ -417,3 +417,21 @@ test('object that is simultaneously a string and a json switched', (t) => {
   const valueObj = stringify({ simultaneously: { foo: likeObjectId } })
   t.is(valueObj, '{"simultaneously":{"foo":"hello"}}')
 })
+
+test('should throw an error when type is array and object is null', (t) => {
+  t.plan(1)
+  const schema = {
+    type: 'object',
+    properties: {
+      arr: {
+        type: 'array',
+        items: {
+          type: 'number'
+        }
+      }
+    }
+  }
+
+  const stringify = build(schema)
+  t.throws(() => stringify({ arr: null }), new TypeError('Property \'arr\' should be of type array, received \'null\' instead.'))
+})