Dont rebuild existing.

Author: jagould2012

standalone.js

@@ -3,9 +3,17 @@
 const fastJsonStringify = require('fast-json-stringify')
 
 function SerializerSelector () {
+  const cache = new Map()
   return function buildSerializerFactory (externalSchemas, serializerOpts) {
     const fjsOpts = Object.assign({}, serializerOpts, { schema: externalSchemas })
-    return responseSchemaCompiler.bind(null, fjsOpts)
+    return function cachedResponseSchemaCompiler (opts) {
+      const key = JSON.stringify(opts.schema)
+      const cached = cache.get(key)
+      if (cached) return cached
+      const result = responseSchemaCompiler(fjsOpts, opts)
+      cache.set(key, result)
+      return result
+    }
   }
 }
 

test/plugin.test.js

@@ -36,6 +36,20 @@ test('basic usage', t => {
   t.assert.equal(result, '{"name":"hello"}')
 })
 
+test('cache hit for identical schemas across factories', t => {
+  t.plan(2)
+  const factory = FjsCompiler()
+
+  const compiler1 = factory(externalSchemas1, fastifyFjsOptionsDefault)
+  const compiler2 = factory(externalSchemas1, fastifyFjsOptionsDefault)
+
+  const serialize1 = compiler1({ schema: sampleSchema })
+  const serialize2 = compiler2({ schema: sampleSchema })
+
+  t.assert.equal(serialize1, serialize2, 'same serializer function returned from cache')
+  t.assert.equal(serialize1({ name: 'cached' }), '{"name":"cached"}')
+})
+
 test('fastify integration', async t => {
   const factory = FjsCompiler()