Decrease overhead of lz-str-wasm (#33)

* Decrease overhead of `lz-str-wasm`

* fmt

* Add inline js injector

Makefile

@@ -1,4 +1,11 @@
 .PHONY: build-wasm
 
+# --reference-types
+
 build-wasm:
-	wasm-pack build --target nodejs bindings/lz-str-wasm
+	wasm-pack build --target nodejs bindings/lz-str-wasm
+	cd bindings/lz-str-wasm && python inject-inline-js.py
+
+build-wasm-browser:
+	wasm-pack build --target web bindings/lz-str-wasm 
+	cd bindings/lz-str-wasm && python inject-inline-js.py

bindings/lz-str-wasm/Cargo.toml

@@ -12,4 +12,7 @@ crate-type = ["cdylib", "rlib"]
 [dependencies]
 js-sys = "0.3.47"
 lz-str = { path = "../.." }
-wasm-bindgen = "0.2.70"
+wasm-bindgen = "0.2.70"
+
+[package.metadata.wasm-pack.profile.release]
+wasm-opt = [ '-O4' ]

bindings/lz-str-wasm/inject-inline-js.py

@@ -0,0 +1,12 @@
+if __name__ == "__main__":
+    js_file_str = None
+    with open('pkg/lz_str_wasm.js', 'r') as file:
+        js_file_str = file.read()
+
+    inline_js = None
+    with open('src/inline.js', 'r') as file:
+        inline_js = file.read()
+
+    js_file_str += '\n' + inline_js
+    with open('pkg/lz_str_wasm.js', 'w') as file:
+        file.write(js_file_str)

bindings/lz-str-wasm/src/inline.js

@@ -0,0 +1,12 @@
+const CHUNK_SIZE = 10_000;
+
+function convertUint16ArrayToString(array) {
+    let ret = '';
+    let num_chunks = Math.ceil(array.length / CHUNK_SIZE);
+    for(let i = 0; i < array.length; i += CHUNK_SIZE) {
+        let end_index = Math.min(i + CHUNK_SIZE, i + array.length);
+        ret += String.fromCharCode(...array.subarray(i, end_index));
+    }
+
+    return ret;
+}

bindings/lz-str-wasm/src/lib.rs

@@ -1,23 +1,43 @@
 use js_sys::JsString;
+use js_sys::Uint16Array;
 use wasm_bindgen::prelude::*;
 use wasm_bindgen::JsCast;
 
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(js_name = "convertUint16ArrayToString")]
+    fn convert_uint16_array_to_string(array: &Uint16Array) -> JsString;
+}
+
 /// Compress a [`JsString`].
 #[wasm_bindgen]
-pub fn compress(data: &JsValue) -> JsString {
-    let data: &JsString = data.dyn_ref::<JsString>().expect("invalid `JsString`");
+pub fn compress(data: &JsValue) -> JsValue {
+    let data: &JsString = match data.dyn_ref::<JsString>() {
+        Some(data) => data,
+        None => {
+            return JsValue::NULL;
+        }
+    };
     let data: Vec<u16> = data.iter().collect();
     let compressed = lz_str::compress(&data);
-    JsString::from_char_code(&compressed)
+    let array: Uint16Array = compressed.as_slice().into();
+    convert_uint16_array_to_string(&array).into()
 }
 
 /// Decompress a [`JsString`].
 #[wasm_bindgen]
 pub fn decompress(data: &JsValue) -> JsValue {
-    let data: &JsString = data.dyn_ref::<JsString>().expect("invalid `JsString`");
+    let data: &JsString = match data.dyn_ref::<JsString>() {
+        Some(data) => data,
+        None => {
+            return JsValue::NULL;
+        }
+    };
     let data: Vec<u16> = data.iter().collect();
     lz_str::decompress(&data)
-        .map(|s| JsString::from_char_code(&s))
-        .map(Into::into)
+        .map(|decompressed| {
+            let array: Uint16Array = decompressed.as_slice().into();
+            convert_uint16_array_to_string(&array).into()
+        })
         .unwrap_or(JsValue::NULL)
 }