feat: support async schema/fragment loading, closes #5

Author: epoberezkin

keywords/add_keyword.js

@@ -20,7 +20,10 @@ module.exports = function (ajv, keyword, jsonPatch, patchSchema) {
                   : $ref;
         var validate = ajv.getSchema(id);
         if (validate) return validate.schema;
-        throw new Error('can\'t resolve reference ' + $ref + ' from id ' + it.baseId);
+        var err = new Error('can\'t resolve reference ' + $ref + ' from id ' + it.baseId);
+        err.missingRef = it.resolve.url(it.baseId, $ref);
+        err.missingSchema = it.resolve.normalizeId(it.resolve.fullPath(err.missingRef));
+        throw err;
       }
     },
     metaSchema: {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ajv-merge-patch",
-  "version": "2.0.2",
+  "version": "2.1.0",
   "description": "$merge and $patch keywords for Ajv JSON-Schema validator to extend schemas",
   "main": "index.js",
   "scripts": {

spec/async.spec.js

@@ -0,0 +1,68 @@
+'use strict';
+
+var Ajv = require('ajv');
+var addKeywords = require('..');
+var test = require('./test_validate');
+var assert = require('assert');
+
+describe('async schema loading', function() {
+  var ajv, loadCount;
+
+  beforeEach(function() {
+    ajv = new Ajv({v5: true, loadSchema: loadSchema});
+    addKeywords(ajv);
+    loadCount = 0;
+  });
+
+  describe('$merge', function() {
+    it('should load missing schemas', function (done) {
+      var schema = {
+        "$merge": {
+          "source": { "$ref": "obj.json#" },
+          "with": {
+            "properties": { "q": { "type": "number" } }
+          }
+        }
+      };
+
+      testAsync(schema, '$merge', done);
+    });
+  });
+
+  describe('$patch', function() {
+    it('should load missing schemas', function (done) {
+      var schema = {
+        "$patch": {
+          "source": { "$ref": "obj.json#" },
+          "with": [
+            { "op": "add", "path": "/properties/q", "value": { "type": "number" } }
+          ]
+        }
+      };
+
+      testAsync(schema, '$patch', done);
+    });
+  });
+
+  function testAsync(schema, keyword, done) {
+    ajv.compileAsync(schema, function (err, validate) {
+      if (err) done(err);
+      assert.strictEqual(loadCount, 1);
+      test(validate, keyword);
+      done();
+    });
+  }
+
+  function loadSchema(ref, callback) {
+    if (ref == 'obj.json') {
+      loadCount++;
+      return callback(null, {
+        "id": "obj.json#",
+        "type": "object",
+        "properties": { "p": { "type": "string" } },
+        "additionalProperties": false
+      });
+    }
+    callback(new Error('404: ' + ref));
+  }
+});

spec/patch.spec.js

@@ -37,9 +37,9 @@ describe('keyword $patch', function() {
   });
 
   it('should extend schema defined in $ref', function() {
-    ajvInstances.forEach(testMerge);
+    ajvInstances.forEach(testPatch);
 
-    function testMerge(ajv) {
+    function testPatch(ajv) {
       var sourceSchema = {
         "id": "obj.json#",
         "type": "object",
@@ -64,9 +64,9 @@ describe('keyword $patch', function() {
   });
 
   it('should extend schema defined with relative $ref', function() {
-    ajvInstances.forEach(testMerge);
+    ajvInstances.forEach(testPatch);
 
-    function testMerge(ajv) {
+    function testPatch(ajv) {
       var schema = {
         "id": "obj.json#",
         "definitions": {