From 436d2032c4aeac23434732ad374c3a46883aa5cd Mon Sep 17 00:00:00 2001
From: Kerollmops <clement@meilisearch.com>
Date: Mon, 11 Apr 2022 15:40:07 -0700
Subject: [PATCH 1/2] Add benchmarks to the flatten-serde-json subcrate

---
 flatten-serde-json/Cargo.toml            |  9 +++--
 flatten-serde-json/benches/benchmarks.rs | 42 ++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 2 deletions(-)
 create mode 100644 flatten-serde-json/benches/benchmarks.rs

diff --git a/flatten-serde-json/Cargo.toml b/flatten-serde-json/Cargo.toml
index 7c18656f1..0220e8ceb 100644
--- a/flatten-serde-json/Cargo.toml
+++ b/flatten-serde-json/Cargo.toml
@@ -5,7 +5,12 @@ edition = "2021"
 description = "Flatten serde-json objects like elastic search"
 readme = "README.md"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
 [dependencies]
 serde_json = "1.0"
+
+[dev-dependencies]
+criterion = { version = "0.3", features = ["html_reports"] }
+
+[[bench]]
+name = "benchmarks"
+harness = false
diff --git a/flatten-serde-json/benches/benchmarks.rs b/flatten-serde-json/benches/benchmarks.rs
new file mode 100644
index 000000000..6536bb513
--- /dev/null
+++ b/flatten-serde-json/benches/benchmarks.rs
@@ -0,0 +1,42 @@
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
+use flatten_serde_json::flatten;
+use serde_json::json;
+
+pub fn flatten_simple(c: &mut Criterion) {
+    let mut input = json!({
+      "a": {
+        "b": "c",
+        "d": "e",
+        "f": "g"
+      }
+    });
+    let object = input.as_object_mut().unwrap();
+
+    c.bench_with_input(BenchmarkId::new("flatten", "simple"), &object, |b, input| {
+        b.iter(|| flatten(input))
+    });
+}
+
+pub fn flatten_complex(c: &mut Criterion) {
+    let mut input = json!({
+      "a": [
+        "b",
+        ["c", "d"],
+        { "e": ["f", "g"] },
+        [
+            { "h": "i" },
+            { "e": ["j", { "z": "y" }] },
+        ],
+        ["l"],
+        "m",
+      ]
+    });
+    let object = input.as_object_mut().unwrap();
+
+    c.bench_with_input(BenchmarkId::new("flatten", "complex"), &object, |b, input| {
+        b.iter(|| flatten(input))
+    });
+}
+
+criterion_group!(benches, flatten_simple, flatten_complex);
+criterion_main!(benches);

From b3cec1a3832a4663635c873a700fbb4cc1089108 Mon Sep 17 00:00:00 2001
From: Kerollmops <clement@meilisearch.com>
Date: Mon, 11 Apr 2022 16:12:56 -0700
Subject: [PATCH 2/2] Prefer using direct method calls instead of using the
 json macros

---
 flatten-serde-json/src/lib.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/flatten-serde-json/src/lib.rs b/flatten-serde-json/src/lib.rs
index 734ae2a24..8312f5bd6 100644
--- a/flatten-serde-json/src/lib.rs
+++ b/flatten-serde-json/src/lib.rs
@@ -1,6 +1,6 @@
 #![doc = include_str!("../README.md")]
 
-use serde_json::{json, Map, Value};
+use serde_json::{Map, Value};
 
 pub fn flatten(json: &Map<String, Value>) -> Map<String, Value> {
     let mut obj = Map::new();
@@ -42,7 +42,7 @@ fn insert_value(base_json: &mut Map<String, Value>, key: &str, to_insert: Value)
     debug_assert!(!to_insert.is_object());
     debug_assert!(!to_insert.is_array());
 
-    // does the field aleardy exists?
+    // does the field already exists?
     if let Some(value) = base_json.get_mut(key) {
         // is it already an array
         if let Some(array) = value.as_array_mut() {
@@ -50,16 +50,18 @@ fn insert_value(base_json: &mut Map<String, Value>, key: &str, to_insert: Value)
         // or is there a collision
         } else {
             let value = std::mem::take(value);
-            base_json[key] = json!([value, to_insert]);
+            base_json[key] = Value::Array(vec![value, to_insert]);
         }
         // if it does not exist we can push the value untouched
     } else {
-        base_json.insert(key.to_string(), json!(to_insert));
+        base_json.insert(key.to_string(), to_insert);
     }
 }
 
 #[cfg(test)]
 mod tests {
+    use serde_json::json;
+
     use super::*;
 
     #[test]