fix: coerce to default type on strict null eq.

array -> []
object -> []

Author: rhighs

README.md

@@ -590,6 +590,8 @@ Otherwise, instead of raising an error, null values will be coerced as follows:
 - `number` -> `0`
 - `string` -> `""`
 - `boolean` -> `false`
+- `object` -> `{}`
+- `array` -> `[]`
 
 <a name="largearrays"></a>
 #### Large Arrays

index.js

@@ -559,11 +559,23 @@ function buildObject (context, location) {
 
   let functionCode = `
   `
+  let checkNullableCode = `
+  `
+
+  const nullable = schema.nullable === true
+  if (!nullable) {
+    checkNullableCode = `
+      if (obj === null) {
+        obj = {}
+      }
+    `
+  }
 
   functionCode += `
     // ${schemaRef}
     function ${functionName} (input) {
-      const obj = ${toJSON('input')} || {}
+      let obj = ${toJSON('input')}
+      ${checkNullableCode}
 
       ${buildInnerObject(context, location)}
     }
@@ -597,12 +609,25 @@ function buildArray (context, location) {
     schemaRef = schemaRef.replace(context.rootSchemaId, '')
   }
 
+  let checkNullableCode = `
+  `
+
   let functionCode = `
     function ${functionName} (obj) {
       // ${schemaRef}
   `
 
+  const nullable = schema.nullable === true
+  if (!nullable) {
+    checkNullableCode = `
+      if (obj === null) {
+        obj = []
+      }
+    `
+  }
+
   functionCode += `
+    ${checkNullableCode}
     if (!Array.isArray(obj)) {
       throw new TypeError(\`The value of '${schemaRef}' does not match schema definition.\`)
     }

test/typesArray.test.js

@@ -467,7 +467,7 @@ test('class instance that is simultaneously a string and a json', (t) => {
   t.equal(valueObj, '{"simultaneously":{"foo":"hello"}}')
 })
 
-test('should throw an error when type is array and object is null', (t) => {
+test('should not throw an error when type is array and object is null, it should instead coerce to []', (t) => {
   t.plan(1)
   const schema = {
     type: 'object',
@@ -482,7 +482,8 @@ test('should throw an error when type is array and object is null', (t) => {
   }
 
   const stringify = build(schema)
-  t.throws(() => stringify({ arr: null }), new TypeError('The value of \'#/properties/arr\' does not match schema definition.'))
+  const result = stringify({ arr: null })
+  t.equal(result, JSON.stringify({ arr: [] }))
 })
 
 test('should throw an error when type is array and object is not an array', (t) => {