add testSerializationHooks option

index.d.ts

@@ -114,6 +114,7 @@ declare namespace Nedb {
     corruptAlertThreshold?: number;
     compareStrings?(a: string, b: string): number;
     modes?: {fileMode: number, dirMode: number};
+    testSerializationHooks?: boolean;
   }
 
   interface UpdateOptions {

lib/datastore.js

@@ -193,6 +193,8 @@ class Datastore extends EventEmitter {
    * @param {compareStrings} [options.compareStrings] If specified, it overrides default string comparison which is not
    * well adapted to non-US characters in particular accented letters. Native `localCompare` will most of the time be
    * the right choice.
+   * @param {boolean} [options.testSerializationHooks=true] Whether to test the serialization hooks or not,
+   * might be CPU-intensive
    */
   constructor (options) {
     super()
@@ -262,7 +264,8 @@ class Datastore extends EventEmitter {
       afterSerialization: options.afterSerialization,
       beforeDeserialization: options.beforeDeserialization,
       corruptAlertThreshold: options.corruptAlertThreshold,
-      modes: options.modes
+      modes: options.modes,
+      testSerializationHooks: options.testSerializationHooks
     })
 
     // This new executor is ready if we don't use persistence

lib/persistence.js

@@ -49,6 +49,7 @@ class Persistence {
    * @param {object} [options.modes] Modes to use for FS permissions. Will not work on Windows.
    * @param {number} [options.modes.fileMode=0o644] Mode to use for files.
    * @param {number} [options.modes.dirMode=0o755] Mode to use for directories.
+   * @param {boolean} [options.testSerializationHooks=true] Whether to test the serialization hooks or not, might be CPU-intensive
    */
   constructor (options) {
     this.db = options.db
@@ -77,11 +78,13 @@ class Persistence {
     this.afterSerialization = options.afterSerialization || (s => s)
     this.beforeDeserialization = options.beforeDeserialization || (s => s)
 
-    for (let i = 1; i < 30; i += 1) {
+    if (options.testSerializationHooks === undefined || options.testSerializationHooks) {
-      for (let j = 0; j < 10; j += 1) {
+      for (let i = 1; i < 30; i += 1) {
-        const randomString = customUtils.uid(i)
+        for (let j = 0; j < 10; j += 1) {
-        if (this.beforeDeserialization(this.afterSerialization(randomString)) !== randomString) {
+          const randomString = customUtils.uid(i)
-          throw new Error('beforeDeserialization is not the reverse of afterSerialization, cautiously refusing to start NeDB to prevent dataloss')
+          if (this.beforeDeserialization(this.afterSerialization(randomString)) !== randomString) {
+            throw new Error('beforeDeserialization is not the reverse of afterSerialization, cautiously refusing to start NeDB to prevent dataloss')
+          }
         }
       }
     }

test/persistence.async.test.js

@@ -461,6 +461,20 @@ describe('Persistence async', function () {
       assert.equal(await fs.readFile(hookTestFilename, 'utf8'), 'Some content')
     })
 
+    it('Declaring two hooks that are not reverse of one another will not cause exception if options.testSerializationHooks === false', async () => {
+      const hookTestFilename = 'workspace/hookTest.db'
+      await storage.ensureFileDoesntExistAsync(hookTestFilename)
+      await fs.writeFile(hookTestFilename, 'Some content', 'utf8')
+      const db = new Datastore({
+        filename: hookTestFilename,
+        autoload: true,
+        afterSerialization: as,
+        beforeDeserialization: function (s) { return s },
+        testSerializationHooks: false
+      })
+      await assert.rejects(() => db.autoloadPromise)
+    })
+
     it('A serialization hook can be used to transform data before writing new state to disk', async () => {
       const hookTestFilename = 'workspace/hookTest.db'
       await storage.ensureFileDoesntExistAsync(hookTestFilename)