From 3c47ae9fe47b39ea1073b7598c77dbf7abe94fd1 Mon Sep 17 00:00:00 2001
From: Mateusz Loskot <mateusz@loskot.net>
Date: Tue, 30 Jun 2015 11:33:44 +0200
Subject: [PATCH] Add to FAQ: How to clear-and-minimize a document?

Closes #368
---
 doc/faq.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/doc/faq.md b/doc/faq.md
index b00b4c6..093e8e7 100644
--- a/doc/faq.md
+++ b/doc/faq.md
@@ -102,6 +102,21 @@
 
    Some applications use 64-bit unsigned/signed integers. And these integers cannot be converted into `double` without loss of precision. So the parsers detects whether a JSON number is convertible to different types of integers and/or `double`.
 
+8. How to clear-and-minimize a document or value?
+
+* Call one of the `SetXXX()` methods - they call destructor which deallocates DOM data:
+
+   ```
+   Document d;
+   ...
+   d.SetObject();  // clear and minimize
+   ```
+
+* Alternatively, use equivalent of the [C++ swap with temporary idiom](https://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Clear-and-minimize):
+   ```
+   d.Swap(Value(kObjectType).Move()) 
+   ```
+
 ## Document/Value (DOM)
 
 1. What is move semantics? Why?