From 5e644ed05d5fd28faae52915f06ca0bee66ea51f Mon Sep 17 00:00:00 2001
From: boyned//Kampfkarren <boynedmaster@gmail.com>
Date: Mon, 31 May 2021 21:29:35 -0700
Subject: [PATCH] Add json.toStringPretty (#55)

* Add json.toStringPretty

* Add optional indentation

* Better changelog

* Update src/remodel_api/json.rs

Co-authored-by: Lucien Greathouse <me@lpghatguy.com>
---
 CHANGELOG.md                 |  1 +
 README.md                    |  9 +++++++++
 src/remodel_api/json.rs      | 26 +++++++++++++++++++++++++-
 test-scripts/json-encode.lua | 32 +++++++++++++++++++++++++++++++-
 4 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c522394..20b12b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 * Added support for CFrame ([#48](https://github.com/rojo-rbx/remodel/pull/48))
 * Added support for Vector3, and improved Vector3int16 ([#46](https://github.com/rojo-rbx/remodel/pull/46))
 * Added Color3.fromRGB(red, blue, green) ([#44](https://github.com/rojo-rbx/remodel/pull/44))
+* Added `json.toStringPretty` ([#55](https://github.com/rojo-rbx/remodel/pull/55))
 
 ## 0.8.1 (2021-04-09)
 * Updated to latest rbx_xml, which should fix `OptionalCoordinateFrame`-related issues.
diff --git a/README.md b/README.md
index 2d56b21..90edc82 100644
--- a/README.md
+++ b/README.md
@@ -280,6 +280,15 @@ Encodes a Lua object as a JSON string. Can only encode Lua primitives like table
 
 Throws on error, like if the input table cannot be encoded.
 
+### `json.toStringPretty` (Unreleased)
+```
+json.toStringPretty(value: any, indent?: string = "  "): string
+```
+
+Encodes a Lua object as a prettified JSON string. If an indent is passed, will use that for indentation, otherwise will default to two spaces.
+
+Throws on error, like if the input table cannot be encoded.
+
 ## Supported Roblox Types
 When interacting with Roblox instances, Remodel doesn't support all value types yet and may throw an error.
 
diff --git a/src/remodel_api/json.rs b/src/remodel_api/json.rs
index eeaf097..83c83f9 100644
--- a/src/remodel_api/json.rs
+++ b/src/remodel_api/json.rs
@@ -1,5 +1,9 @@
 use rlua::{Context, FromLua, Table, ToLua, UserData, UserDataMethods, Value as LuaValue};
-use serde_json::{Number, Value as JsonValue};
+use serde::Serialize;
+use serde_json::{
+    ser::{PrettyFormatter, Serializer},
+    Number, Value as JsonValue,
+};
 
 pub struct Json;
 
@@ -9,6 +13,26 @@ impl UserData for Json {
             serde_json::to_string(&lua_value.0).map_err(rlua::Error::external)
         });
 
+        methods.add_function(
+            "toStringPretty",
+            |_context, (lua_value, indent): (Value, Option<String>)| {
+                let pretty_formatter = if let Some(ref indent) = indent {
+                    PrettyFormatter::with_indent(indent.as_bytes())
+                } else {
+                    PrettyFormatter::new()
+                };
+
+                let mut output = Vec::new();
+                let mut serializer = Serializer::with_formatter(&mut output, pretty_formatter);
+                lua_value
+                    .0
+                    .serialize(&mut serializer)
+                    .map_err(rlua::Error::external)?;
+
+                String::from_utf8(output).map_err(rlua::Error::external)
+            },
+        );
+
         methods.add_function("fromString", |_context, source: String| {
             serde_json::from_str::<JsonValue>(&source)
                 .map(Value)
diff --git a/test-scripts/json-encode.lua b/test-scripts/json-encode.lua
index 8a067fc..3f291f5 100644
--- a/test-scripts/json-encode.lua
+++ b/test-scripts/json-encode.lua
@@ -17,4 +17,34 @@ assert(encodedSparse == "[1.0,2.0,null,4.0]")
 
 local sparser = {1, 2, 3, [1000] = 6}
 local encodedSparser = json.toString(sparser)
-assert(encodedSparser == [[{"1":1.0,"1000":6.0,"2":2.0,"3":3.0}]])
\ No newline at end of file
+assert(encodedSparser == [[{"1":1.0,"1000":6.0,"2":2.0,"3":3.0}]])
+
+local encodedPretty = json.toStringPretty(baseline)
+assert(encodedPretty == [[{
+  "w": {
+    "0": "cool",
+    "wack": "yo"
+  },
+  "x": 5.0,
+  "y": "Hello, world!",
+  "z": [
+    1.0,
+    2.0,
+    3.0
+  ]
+}]])
+
+local encodedPrettyWithIndent = json.toStringPretty(baseline, "\t")
+assert(encodedPrettyWithIndent == [[{
+	"w": {
+		"0": "cool",
+		"wack": "yo"
+	},
+	"x": 5.0,
+	"y": "Hello, world!",
+	"z": [
+		1.0,
+		2.0,
+		3.0
+	]
+}]])