From 2c1a9171c689c1fc87428d383ffeb823291f84cf Mon Sep 17 00:00:00 2001
From: Durran Jordan <durran@gmail.com>
Date: Fri, 6 May 2022 14:51:32 -0400
Subject: [PATCH] feat(NODE-1837): support passing compression level

---
 index.d.ts         |  2 +-
 src/lib.rs         | 10 +++++++---
 test/index.test.js | 33 ++++++++++++++++++++++++++++++---
 3 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/index.d.ts b/index.d.ts
index 51188c8..8d16577 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -3,5 +3,5 @@
 
 /* auto-generated by NAPI-RS */
 
-export function compress(data: Buffer): Promise<Buffer>
+export function compress(data: Buffer, level?: number | undefined | null): Promise<Buffer>
 export function decompress(data: Buffer): Promise<Buffer>
diff --git a/src/lib.rs b/src/lib.rs
index 6cf7426..6d3b134 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,8 +7,11 @@ use napi::{
 };
 use zstd::stream::{encode_all, decode_all};
 
+const DEFAULT_LEVEL: i32 = 3;
+
 struct Encoder {
-  data: Ref<JsBufferValue>
+  data: Ref<JsBufferValue>,
+  level: i32
 }
 
 #[napi]
@@ -18,7 +21,7 @@ impl Task for Encoder {
 
   fn compute(&mut self) -> Result<Self::Output> {
     let data: &[u8] = self.data.as_ref();
-    encode_all(data, 3).map_err(|e| Error::new(Status::GenericFailure, format!("{}", e)))
+    encode_all(data, self.level).map_err(|e| Error::new(Status::GenericFailure, format!("{}", e)))
   }
 
   fn resolve(&mut self, env: Env, output: Self::Output) -> Result<JsBuffer> {
@@ -56,9 +59,10 @@ impl Task for Decoder {
 }
 
 #[napi]
-fn compress(data: JsBuffer) -> Result<AsyncTask<Encoder>> {
+fn compress(data: JsBuffer, level: Option<i32>) -> Result<AsyncTask<Encoder>> {
   let encoder = Encoder {
     data: data.into_ref()?,
+    level: level.unwrap_or(DEFAULT_LEVEL)
   };
   Ok(AsyncTask::new(encoder))
 }
diff --git a/test/index.test.js b/test/index.test.js
index 753e871..781f005 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -5,9 +5,36 @@ describe('zstd', () => {
   describe('#compress', () => {
     const buffer = Buffer.from('test');
 
-    it('returns a compressed buffer', async () => {
-      const result = await compress(buffer);
-      expect(await decompress(result)).to.deep.equal(buffer);
+    context('when not providing a compression level', () => {
+      it('returns a compressed buffer', async () => {
+        const result = await compress(buffer);
+        expect(await decompress(result)).to.deep.equal(buffer);
+      });
+    });
+
+    context('when providing a compression level', () => {
+      context('when the level is valid', () => {
+        it('returns a compressed buffer', async () => {
+          const result = await compress(buffer, 1);
+          expect(await decompress(result)).to.deep.equal(buffer);
+        });
+      });
+
+      context('when the level is invalid', () => {
+        context('when the level is too high', () => {
+          it('returns a compressed buffer', async () => {
+            const result = await compress(buffer, 100);
+            expect(await decompress(result)).to.deep.equal(buffer);
+          });
+        });
+
+        context('when the level is too low', () => {
+          it('returns a compressed buffer', async () => {
+            const result = await compress(buffer, -100);
+            expect(await decompress(result)).to.deep.equal(buffer);
+          });
+        });
+      });
     });
   });
 });