fix/$ref on root schema (#163)

* fix: $ref in root schema

* add: multiple root $ref

Author: Eomm

index.js

@@ -71,6 +71,10 @@ function build (schema, options) {
     `
   }
 
+  if (schema['$ref']) {
+    schema = refFinder(schema['$ref'], schema, options.schema)
+  }
+
   if (schema.type === undefined) {
     schema.type = inferTypeByKeyword(schema)
   }
@@ -477,6 +481,10 @@ function refFinder (ref, schema, externalSchema) {
   // If external file
   if (ref[0]) {
     schema = externalSchema[ref[0]]
+
+    if (schema['$ref']) {
+      return refFinder(schema['$ref'], schema, externalSchema)
+    }
   }
 
   var code = 'return schema'

test/ref.test.js

@@ -684,3 +684,85 @@ test('ref internal - multiple $ref format', (t) => {
 
   t.equal(output, '{"zero":"test","a":"test","b":"test","c":"test","d":"test","e":"test"}')
 })
+
+test('ref in root external', (t) => {
+  t.plan(2)
+
+  const externalSchema = {
+    numbers: {
+      $id: 'numbers',
+      definitions: {
+        num: {
+          type: 'object',
+          properties: {
+            int: {
+              type: 'integer'
+            }
+          }
+        }
+      }
+    }
+  }
+
+  const schema = {
+    title: 'object with $ref in root schema',
+    type: 'object',
+    $ref: 'numbers#/definitions/num'
+  }
+
+  const object = { int: 42 }
+  const stringify = build(schema, { schema: externalSchema })
+  const output = stringify(object)
+
+  try {
+    JSON.parse(output)
+    t.pass()
+  } catch (e) {
+    t.fail()
+  }
+
+  t.equal(output, '{"int":42}')
+})
+
+test('ref in root external multiple times', (t) => {
+  t.plan(2)
+
+  const externalSchema = {
+    numbers: {
+      $id: 'numbers',
+      $ref: 'subnumbers#/definitions/num'
+    },
+    subnumbers: {
+      $id: 'subnumbers',
+      definitions: {
+        num: {
+          type: 'object',
+          properties: {
+            int: {
+              type: 'integer'
+            }
+          }
+        }
+      }
+    }
+  }
+
+  const schema = {
+    title: 'object with $ref in root schema',
+    type: 'object',
+    $ref: 'numbers#/definitions/num'
+  }
+
+  const object = { int: 42 }
+  const stringify = build(schema, { schema: externalSchema })
+  const output = stringify(object)
+
+  try {
+    JSON.parse(output)
+    t.pass()
+  } catch (e) {
+    t.fail()
+  }
+
+  t.equal(output, '{"int":42}')
+})