Update to ajv version 7.2.3 (#307)

* Migrate to ajv 7

* Add `$validateWithAjv` function to leverage ajv caching

* Write a description for $validateWithAjv function

* Improve $validateWithAjv description comment

Author: MSE99

build-schema-validator.js

@@ -1,21 +1,16 @@
 'use strict'
 
-const Ajv = require('ajv')
-const fs = require('fs')
-const path = require('path')
-const pack = require('ajv-pack')
+const Ajv = require('ajv').default
+const schema = require('ajv/dist/refs/json-schema-draft-07.json')
+const standalone = require('ajv/dist/standalone').default
 
-const ajv = new Ajv({
-  sourceCode: true // this option is required by ajv-pack
-})
+const { basename, join } = require('path')
+const { writeFileSync } = require('fs')
 
-const validate = ajv.compile(require('ajv/lib/refs/json-schema-draft-07.json'))
+// *************************
 
-const moduleCode = `// This file is autogenerated by ${path.basename(__filename)}, do not edit
+const ajv = new Ajv({ code: { source: true } })
+const validator = ajv.compile(schema)
+const moduleCode = `/* CODE GENERATED BY '${basename(__filename)}' DO NOT EDIT! */\n${standalone(ajv, validator)}`
 
-function nop () { return true }
-
-${pack(ajv, validate).replace(/root\.refVal\[0\]/gm, 'nop')}
-`
-
-fs.writeFileSync(path.join(__dirname, 'schema-validator.js'), moduleCode)
+writeFileSync(join(__dirname, 'schema-validator.js'), moduleCode)

index.js

@@ -2,7 +2,7 @@
 
 /* eslint no-prototype-builtins: 0 */
 
-const Ajv = require('ajv')
+const Ajv = require('ajv').default
 const merge = require('deepmerge')
 const clone = require('rfdc')({ proto: true })
 const fjsCloned = Symbol('fast-json-stringify.cloned')
@@ -87,6 +87,40 @@ function build (schema, options) {
     ${$asBoolean.toString()}
     ${$asBooleanNullable.toString()}
 
+    
+    /**
+     * Used by schemas that are dependant on calling 'ajv.validate' during runtime,
+     * it stores the value of the '$id' property of the schema (if it has it) inside
+     * a cache which is used to figure out if the schema was compiled into a validator
+     * by ajv on a previous call, if it was then the '$id' string will be used to 
+     * invoke 'ajv.validate', this allows:
+     * 
+     * 1. Schemas that depend on ajv.validate calls to leverage ajv caching system.
+     * 2. To avoid errors, since directly invoking 'ajv.validate' with the same 
+     * schema (that contains an '$id' property) twice will throw an error.
+     */
+    const $validateWithAjv = (function() {
+      const cache = new Set()
+
+      return function (schema, target) {
+        const id = schema.$id
+        
+        if (!id) {
+          return ajv.validate(schema, target)
+        }
+
+        const cached = cache.has(id)
+
+        if (cached) {
+          return ajv.validate(id, target)
+        } else {
+          cache.add(id)
+          return ajv.validate(schema, target)
+        }
+      }
+    })()
+
+
     var isLong = ${isLong ? isLong.toString() : false}
 
     function parseInteger(int) { return Math.${intParseFunctionName}(int) }
@@ -870,7 +904,7 @@ function addIfThenElse (location, name) {
   let mergedLocation = mergeLocation(location, { schema: merged })
 
   code += `
-    valid = ajv.validate(${JSON.stringify(i)}, obj)
+    valid = $validateWithAjv(${JSON.stringify(i)}, obj)
     if (valid) {
   `
   if (merged.if && merged.then) {
@@ -1189,7 +1223,7 @@ function nested (laterCode, name, key, location, subKey, isArray) {
           // 2. `nested`, through `buildCode`, replaces any reference in object properties with the actual schema
           // (see https://github.com/fastify/fast-json-stringify/blob/6da3b3e8ac24b1ca5578223adedb4083b7adf8db/index.js#L631)
           code += `
-            ${index === 0 ? 'if' : 'else if'}(ajv.validate(${JSON.stringify(location.schema)}, obj${accessor}))
+            ${index === 0 ? 'if' : 'else if'}($validateWithAjv(${JSON.stringify(location.schema)}, obj${accessor}))
               ${nestedResult.code}
           `
           laterCode = nestedResult.laterCode
@@ -1205,7 +1239,7 @@ function nested (laterCode, name, key, location, subKey, isArray) {
 
           // see comment on anyOf about derefencing the schema before calling ajv.validate
           code += `
-            ${index === 0 ? 'if' : 'else if'}(ajv.validate(${JSON.stringify(location.schema)}, obj${accessor}))
+            ${index === 0 ? 'if' : 'else if'}($validateWithAjv(${JSON.stringify(location.schema)}, obj${accessor}))
               ${nestedResult.code}
           `
           laterCode = nestedResult.laterCode

package.json

@@ -30,7 +30,6 @@
   },
   "homepage": "https://github.com/fastify/fast-json-stringify#readme",
   "devDependencies": {
-    "ajv-pack": "^0.3.1",
     "benchmark": "^2.1.4",
     "compile-json-stringify": "^0.1.2",
     "is-my-json-valid": "^2.20.0",
@@ -44,7 +43,7 @@
     "typescript": "^4.0.2"
   },
   "dependencies": {
-    "ajv": "^6.11.0",
+    "ajv": "^7.2.3",
     "deepmerge": "^4.2.2",
     "rfdc": "^1.2.0",
     "string-similarity": "^4.0.1"