Javascript bindings (#14)

* Initial version ready - bindings are in `bindings/emscripten.cpp` - minimal Javascript example is in `examples/ggwave-js` * add npm package + add test-ggwave.js * js : rename export name to "ggwave_factory" * update to v0.1.5 * Update README.md * npm : add npm-publish target
2026-02-06 08:37:59 +08:00 · 2021-01-24 17:25:58 +02:00
parent 105e0fd48d
commit 19f353018d
19 changed files with 485 additions and 57 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,8 +1,10 @@
 cmake_minimum_required (VERSION 3.0)
-project(ggwave VERSION 0.1.4)
+project(ggwave VERSION 0.1.5)

+# configure project version
 configure_file(${CMAKE_SOURCE_DIR}/README.md.tmpl ${CMAKE_SOURCE_DIR}/README.md @ONLY)
 configure_file(${CMAKE_SOURCE_DIR}/bindings/python/setup.py.tmpl ${CMAKE_SOURCE_DIR}/bindings/python/setup.py @ONLY)
+configure_file(${CMAKE_SOURCE_DIR}/bindings/javascript/package-tmpl.json ${CMAKE_SOURCE_DIR}/bindings/javascript/package.json @ONLY)

 set(CMAKE_EXPORT_COMPILE_COMMANDS "on")
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
@@ -75,48 +77,7 @@ if (GGWAVE_ALL_WARNINGS)
 endif()

 add_subdirectory(src)
-
-if (GGWAVE_SUPPORT_PYTHON)
-    file(GLOB_RECURSE GGWAVE_SOURCES "include/*" "src/*")
-
-    add_custom_command(
-        OUTPUT ${CMAKE_SOURCE_DIR}/bindings/python/ggwave.bycython.cpp
-        OUTPUT ${CMAKE_SOURCE_DIR}/bindings/python/ggwave
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/Makefile
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/ggwave.pyx
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/cggwave.pxd
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/setup.py
-        DEPENDS ${GGWAVE_SOURCES}
-        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/bindings/python
-        COMMAND make clean
-        COMMAND make
-        COMMENT "Compiling Python module"
-        VERBATIM
-        )
-
-    add_custom_target(ggwave-py ALL
-        DEPENDS bindings/python/ggwave.bycython.cpp
-        DEPENDS bindings/python/ggwave
-        )
-
-    add_custom_command(
-        OUTPUT ${CMAKE_SOURCE_DIR}/bindings/python/dist
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/Makefile
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/ggwave.pyx
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/cggwave.pxd
-        DEPENDS ${CMAKE_SOURCE_DIR}/bindings/python/setup.py
-        DEPENDS ${GGWAVE_SOURCES}
-        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/bindings/python
-        COMMAND make publish
-        COMMENT "Publishing Python module v${PROJECT_VERSION}"
-        VERBATIM
-        )
-
-    add_custom_target(pypi-publish
-        DEPENDS bindings/python/dist
-        )
-endif()
-
+add_subdirectory(bindings)

 if (GGWAVE_BUILD_TESTS)
    enable_testing()
--- a/README.md
+++ b/README.md
@@ -4,6 +4,7 @@
 [![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](https://opensource.org/licenses/MIT)
 [![ggwave badge][changelog-badge]][changelog]
 [![pypi](https://img.shields.io/pypi/v/ggwave.svg)](https://pypi.org/project/ggwave/)
+[![npm](https://img.shields.io/npm/v/ggwave.svg)](https://www.npmjs.com/package/ggwave/)

 Tiny data-over-sound library.

@@ -88,14 +89,15 @@ Reed-Solomon decoding is finally performed to obtain the original data.
 The [examples](https://github.com/ggerganov/ggwave/blob/master/examples/) folder contains several sample applications of the library:


-| Example | Description | Backend |
-| ------- | ----------- | ------- |
+| Example | Description | Audio |
+| ------- | ----------- | ----- |
 | [ggwave-rx](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-rx) | Very basic receive-only program | SDL |
 | [ggwave-cli](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-cli) | Command line tool for sending/receiving data through sound | SDL |
 | [ggwave-wasm](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-wasm) | WebAssembly module for web applications | SDL |
 | [ggwave-to-file](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-to-file) | Output a generated waveform to an uncompressed WAV file | - |
 | [waver](https://github.com/ggerganov/ggwave/blob/master/examples/waver) | GUI application for sending/receiving data through sound | SDL |
-| [ggwave-py](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-py) | Python examples | - |
+| [ggwave-py](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-py) | Python examples | PortAudio |
+| [ggwave-js](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-js) | Javascript example | Web Audio API |

 Other projects using **ggwave** or one of its prototypes:

@@ -147,6 +149,14 @@ pip install ggwave

 More info: https://pypi.org/project/ggwave/

+### Node.js
+
+```bash
+npm install ggwave
+```
+
+More info: https://www.npmjs.com/package/ggwave
+
 ## Installing the Waver application

 [![Get it from the Snap Store](https://snapcraft.io/static/images/badges/en/snap-store-black.svg)](https://snapcraft.io/waver)
@@ -165,5 +175,5 @@ sudo snap connect waver:audio-record :audio-record
  ```

 [changelog]: ./CHANGELOG.md
-[changelog-badge]: https://img.shields.io/badge/changelog-ggwave%20v0.1.4-dummy
+[changelog-badge]: https://img.shields.io/badge/changelog-ggwave%20v0.1.5-dummy
 [license]: ./LICENSE
--- a/README.md.tmpl
+++ b/README.md.tmpl
@@ -4,6 +4,7 @@
 [![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](https://opensource.org/licenses/MIT)
 [![ggwave badge][changelog-badge]][changelog]
 [![pypi](https://img.shields.io/pypi/v/ggwave.svg)](https://pypi.org/project/ggwave/)
+[![npm](https://img.shields.io/npm/v/ggwave.svg)](https://www.npmjs.com/package/ggwave/)

 Tiny data-over-sound library.

@@ -88,14 +89,15 @@ Reed-Solomon decoding is finally performed to obtain the original data.
 The [examples](https://github.com/ggerganov/ggwave/blob/master/examples/) folder contains several sample applications of the library:


-| Example | Description | Backend |
-| ------- | ----------- | ------- |
+| Example | Description | Audio |
+| ------- | ----------- | ----- |
 | [ggwave-rx](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-rx) | Very basic receive-only program | SDL |
 | [ggwave-cli](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-cli) | Command line tool for sending/receiving data through sound | SDL |
 | [ggwave-wasm](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-wasm) | WebAssembly module for web applications | SDL |
 | [ggwave-to-file](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-to-file) | Output a generated waveform to an uncompressed WAV file | - |
 | [waver](https://github.com/ggerganov/ggwave/blob/master/examples/waver) | GUI application for sending/receiving data through sound | SDL |
-| [ggwave-py](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-py) | Python examples | - |
+| [ggwave-py](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-py) | Python examples | PortAudio |
+| [ggwave-js](https://github.com/ggerganov/ggwave/blob/master/examples/ggwave-js) | Javascript example | Web Audio API |

 Other projects using **ggwave** or one of its prototypes:

@@ -147,6 +149,14 @@ pip install ggwave

 More info: https://pypi.org/project/ggwave/

+### Node.js
+
+```bash
+npm install ggwave
+```
+
+More info: https://www.npmjs.com/package/ggwave
+
 ## Installing the Waver application

 [![Get it from the Snap Store](https://snapcraft.io/static/images/badges/en/snap-store-black.svg)](https://snapcraft.io/waver)
--- a/bindings/CMakeLists.txt
+++ b/bindings/CMakeLists.txt
@@ -0,0 +1,60 @@
+if (EMSCRIPTEN)
+    add_subdirectory(javascript)
+
+    add_custom_command(
+        OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/javascript/publish.log
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/javascript/ggwave.js
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/javascript/package.json
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/javascript
+        COMMAND npm publish
+        COMMAND touch publish.log
+        COMMENT "Publishing npm module v${PROJECT_VERSION}"
+        VERBATIM
+        )
+
+    add_custom_target(npm-publish
+        DEPENDS javascript/publish.log
+        )
+endif()
+
+if (GGWAVE_SUPPORT_PYTHON)
+    file(GLOB_RECURSE GGWAVE_SOURCES "../include/*" "../src/*")
+
+    add_custom_command(
+        OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/python/ggwave.bycython.cpp
+        OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/python/ggwave
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/Makefile
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/ggwave.pyx
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/cggwave.pxd
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/setup.py
+        DEPENDS ${GGWAVE_SOURCES}
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/python
+        COMMAND make clean
+        COMMAND make
+        COMMENT "Compiling Python module"
+        VERBATIM
+        )
+
+    add_custom_target(ggwave-py ALL
+        DEPENDS python/ggwave.bycython.cpp
+        DEPENDS python/ggwave
+        )
+
+    add_custom_command(
+        OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/python/dist
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/Makefile
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/ggwave.pyx
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/cggwave.pxd
+        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/python/setup.py
+        DEPENDS ${GGWAVE_SOURCES}
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/python
+        COMMAND make publish
+        COMMENT "Publishing Python module v${PROJECT_VERSION}"
+        VERBATIM
+        )
+
+    add_custom_target(pypi-publish
+        DEPENDS python/dist
+        )
+endif()
+
--- a/bindings/javascript/.gitignore
+++ b/bindings/javascript/.gitignore
@@ -0,0 +1 @@
+publish.log
--- a/bindings/javascript/CMakeLists.txt
+++ b/bindings/javascript/CMakeLists.txt
@@ -0,0 +1,24 @@
+set(TARGET libggwave)
+
+add_executable(${TARGET}
+    emscripten.cpp
+    )
+
+target_link_libraries(${TARGET} PRIVATE
+    ggwave
+    )
+
+set_target_properties(${TARGET} PROPERTIES LINK_FLAGS " \
+    --bind \
+    -s MODULARIZE=1 \
+    -s SINGLE_FILE=1 \
+    -s ALLOW_MEMORY_GROWTH=1 \
+    -s EXPORT_NAME=\"'ggwave_factory'\" \
+    ")
+
+add_custom_command(
+    TARGET libggwave POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy
+    ${CMAKE_BINARY_DIR}/bin/libggwave.js
+    ${CMAKE_CURRENT_SOURCE_DIR}/ggwave.js
+    )
--- a/bindings/javascript/emscripten.cpp
+++ b/bindings/javascript/emscripten.cpp
@@ -0,0 +1,65 @@
+#include "ggwave/ggwave.h"
+
+#include <emscripten.h>
+#include <emscripten/bind.h>
+
+EMSCRIPTEN_BINDINGS(ggwave) {
+    emscripten::enum_<ggwave_SampleFormat>("SampleFormat")
+        .value("GGWAVE_SAMPLE_FORMAT_UNDEFINED", GGWAVE_SAMPLE_FORMAT_UNDEFINED)
+        .value("GGWAVE_SAMPLE_FORMAT_U8",  GGWAVE_SAMPLE_FORMAT_U8)
+        .value("GGWAVE_SAMPLE_FORMAT_I8",  GGWAVE_SAMPLE_FORMAT_I8)
+        .value("GGWAVE_SAMPLE_FORMAT_U16", GGWAVE_SAMPLE_FORMAT_U16)
+        .value("GGWAVE_SAMPLE_FORMAT_I16", GGWAVE_SAMPLE_FORMAT_I16)
+        .value("GGWAVE_SAMPLE_FORMAT_F32", GGWAVE_SAMPLE_FORMAT_F32)
+        ;
+
+    emscripten::enum_<ggwave_TxProtocolId>("TxProtocolId")
+        .value("GGWAVE_TX_PROTOCOL_AUDIBLE_NORMAL",     GGWAVE_TX_PROTOCOL_AUDIBLE_NORMAL)
+        .value("GGWAVE_TX_PROTOCOL_AUDIBLE_FAST",       GGWAVE_TX_PROTOCOL_AUDIBLE_FAST)
+        .value("GGWAVE_TX_PROTOCOL_AUDIBLE_FASTEST",    GGWAVE_TX_PROTOCOL_AUDIBLE_FASTEST)
+        .value("GGWAVE_TX_PROTOCOL_ULTRASOUND_NORMAL",  GGWAVE_TX_PROTOCOL_ULTRASOUND_NORMAL)
+        .value("GGWAVE_TX_PROTOCOL_ULTRASOUND_FAST",    GGWAVE_TX_PROTOCOL_ULTRASOUND_FAST)
+        .value("GGWAVE_TX_PROTOCOL_ULTRASOUND_FASTEST", GGWAVE_TX_PROTOCOL_ULTRASOUND_FASTEST)
+        ;
+
+    emscripten::class_<ggwave_Parameters>("Parameters")
+        .constructor<>()
+        .property("sampleRateInp", &ggwave_Parameters::sampleRateInp)
+        .property("sampleRateOut", &ggwave_Parameters::sampleRateOut)
+        .property("samplesPerFrame", &ggwave_Parameters::samplesPerFrame)
+        .property("sampleFormatInp", &ggwave_Parameters::sampleFormatInp)
+        .property("sampleFormatOut", &ggwave_Parameters::sampleFormatOut)
+        ;
+
+    emscripten::function("getDefaultParameters", &ggwave_getDefaultParameters);
+    emscripten::function("init", &ggwave_init);
+    emscripten::function("free", &ggwave_free);
+
+    emscripten::function("encode", emscripten::optional_override(
+                    [](ggwave_Instance instance,
+                       const std::string & data,
+                       ggwave_TxProtocolId txProtocolId,
+                       int volume) {
+                        auto n = ggwave_encode(instance, data.data(), data.size(), txProtocolId, volume, nullptr, 1);
+                        std::vector<char> result(n);
+                        result.resize(n);
+                        ggwave_encode(instance, data.data(), data.size(), txProtocolId, volume, result.data(), 0);
+
+                        return emscripten::val(
+                                emscripten::typed_memory_view(result.size(),
+                                                              result.data()));
+                    }));
+
+    emscripten::function("decode", emscripten::optional_override(
+                    [](ggwave_Instance instance,
+                       const std::string & data) {
+                        char output[256];
+                        auto n = ggwave_decode(instance, data.data(), data.size(), output);
+
+                        if (n > 0) {
+                            return std::string(output, n);
+                        }
+
+                        return std::string();
+                    }));
+}
--- a/bindings/javascript/ggwave.js
+++ b/bindings/javascript/ggwave.js
--- a/bindings/javascript/package-tmpl.json
+++ b/bindings/javascript/package-tmpl.json
@@ -0,0 +1,26 @@
+{
+  "name": "ggwave",
+  "version": "@PROJECT_VERSION@",
+  "description": "Tiny data-over-sound library",
+  "main": "ggwave.js",
+  "scripts": {
+    "test": "echo \"todo: add tests\" && exit 0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/ggerganov/ggwave.git"
+  },
+  "keywords": [
+    "data-over-sound",
+    "fsk",
+    "sound-library",
+    "ultrasound",
+    "ecc"
+  ],
+  "author": "Georgi Gerganov",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/ggerganov/ggwave/issues"
+  },
+  "homepage": "https://github.com/ggerganov/ggwave#readme"
+}
--- a/bindings/javascript/package.json
+++ b/bindings/javascript/package.json
@@ -0,0 +1,26 @@
+{
+  "name": "ggwave",
+  "version": "0.1.5",
+  "description": "Tiny data-over-sound library",
+  "main": "ggwave.js",
+  "scripts": {
+    "test": "echo \"todo: add tests\" && exit 0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/ggerganov/ggwave.git"
+  },
+  "keywords": [
+    "data-over-sound",
+    "fsk",
+    "sound-library",
+    "ultrasound",
+    "ecc"
+  ],
+  "author": "Georgi Gerganov",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/ggerganov/ggwave/issues"
+  },
+  "homepage": "https://github.com/ggerganov/ggwave#readme"
+}
--- a/bindings/python/setup.py
+++ b/bindings/python/setup.py
@@ -30,7 +30,7 @@ setup(
    name = "ggwave",
    description = "Tiny data-over-sound library.",
    long_description = long_description,
-    version = "0.1.4",
+    version = "0.1.5",
    url = "https://github.com/ggerganov/ggwave",
    author = "Georgi Gerganov",
    author_email = "ggerganov@gmail.com",
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -6,7 +6,14 @@ if (GGWAVE_SUPPORT_SDL2)
    # SDL2

    if (EMSCRIPTEN)
-        set(CMAKE_CXX_FLAGS "-s TOTAL_MEMORY=67108864 -s USE_SDL=2 -s ASSERTIONS=1 -s DISABLE_EXCEPTION_CATCHING=0 -s 'EXTRA_EXPORTED_RUNTIME_METHODS=[\"writeArrayToMemory\"]'")
+        set(CMAKE_CXX_FLAGS " \
+        --bind \
+        -s TOTAL_MEMORY=67108864 \
+        -s USE_SDL=2 \
+        -s ASSERTIONS=1 \
+        -s DISABLE_EXCEPTION_CATCHING=0 \
+        -s 'EXTRA_EXPORTED_RUNTIME_METHODS=[\"writeArrayToMemory\"]' \
+        ")

        unset(SDL2_INCLUDE_DIRS)
        unset(SDL2_LIBRARIES)
@@ -65,19 +72,23 @@ endif()

 # examples

-add_subdirectory(ggwave-to-file)
+if (EMSCRIPTEN)
+    add_subdirectory(ggwave-js)
+else()
+    add_subdirectory(ggwave-to-file)
+endif()

 if (GGWAVE_SUPPORT_SDL2)
    if (EMSCRIPTEN)
        # emscripten sdl2 examples

        add_subdirectory(ggwave-wasm)
-        add_subdirectory(waver)
    else()
        # non-emscripten sdl2 examples

        add_subdirectory(ggwave-rx)
        add_subdirectory(ggwave-cli)
-        add_subdirectory(waver)
    endif()
+
+    add_subdirectory(waver)
 endif()
--- a/examples/ggwave-common-sdl2.cpp
+++ b/examples/ggwave-common-sdl2.cpp
@@ -10,7 +10,7 @@
 #include <chrono>

 #ifdef __EMSCRIPTEN__
-#include "emscripten/emscripten.h"
+#include <emscripten.h>
 #else
 #define EMSCRIPTEN_KEEPALIVE
 #endif
--- a/examples/ggwave-js/CMakeLists.txt
+++ b/examples/ggwave-js/CMakeLists.txt
@@ -0,0 +1,3 @@
+set(TARGET ggwave-js)
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/index-tmpl.html ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${TARGET}/index.html @ONLY)
--- a/examples/ggwave-js/index-tmpl.html
+++ b/examples/ggwave-js/index-tmpl.html
@@ -0,0 +1,180 @@
+<!doctype html>
+<html lang="en-us">
+    <head>
+        <title>ggwave : javascript example</title>
+    </head>
+    <body>
+        <div id="main-container">
+            Minimal <b>ggwave</b> example using Javascript bindings
+
+            <br><br>
+
+            <div>Tx Data:</div> <textarea name="textarea" id="txData" style="width:300px;height:100px;">Hello javascript</textarea><br>
+
+            <button onclick="onSend();">Send</button>
+
+            <br><br>
+
+            <div>Rx data:</div> <textarea name="textarea" id="rxData" style="width:300px;height:100px;" disabled></textarea><br>
+
+            <button id="captureStart">Start capturing</button>
+            <button id="captureStop" hidden>Stop capturing</button>
+
+            <br><br>
+
+            <div class="cell-version">
+                <span>
+                    |
+                    Build time: <span class="nav-link">@GIT_DATE@</span> |
+                    Commit hash: <a class="nav-link" href="https://github.com/ggerganov/ggwave/commit/@GIT_SHA1@">@GIT_SHA1@</a> |
+                    Commit subject: <span class="nav-link">@GIT_COMMIT_SUBJECT@</span> |
+                    <a class="nav-link" href="https://github.com/ggerganov/ggwave/tree/master/examples/ggwave-js">Source Code</a> |
+                </span>
+            </div>
+        </div>
+
+        <script type="text/javascript" src="ggwave.js"></script>
+        <script type='text/javascript'>
+            window.AudioContext = window.AudioContext || window.webkitAudioContext;
+            window.OfflineAudioContext = window.OfflineAudioContext || window.webkitOfflineAudioContext;
+
+            var context = null;
+            var recorder = null;
+
+            // the ggwave module instance
+            var ggwave = null;
+            var parameters = null;
+            var instance = null;
+
+            // instantiate the ggwave instance
+            // ggwave_factory comes from the ggwave.js module
+            ggwave_factory().then(function(obj) {
+                ggwave = obj;
+            });
+
+            var txData = document.getElementById("txData");
+            var rxData = document.getElementById("rxData");
+            var captureStart = document.getElementById("captureStart");
+            var captureStop = document.getElementById("captureStop");
+
+            // helper function
+            function convertTypedArray(src, type) {
+                var buffer = new ArrayBuffer(src.byteLength);
+                var baseView = new src.constructor(buffer).set(src);
+                return new type(buffer);
+            }
+
+            // initialize audio context and ggwave
+            function init() {
+                if (!context) {
+                    // todo : query ggwave's base sample rate
+                    context = new AudioContext({sampleRate: 48000});
+
+                    parameters = ggwave.getDefaultParameters();
+                    parameters.sampleRateOut = context.sampleRate;
+                    instance = ggwave.init(parameters);
+                }
+            }
+
+            //
+            // Tx
+            //
+
+            function onSend() {
+                init();
+
+                // pause audio capture during transmission
+                captureStop.click();
+
+                // generate audio waveform
+                var waveform = ggwave.encode(instance, txData.value, ggwave.TxProtocolId.GGWAVE_TX_PROTOCOL_AUDIBLE_FAST, 10)
+
+                // play audio
+                var buf = convertTypedArray(waveform, Float32Array);
+                var buffer = context.createBuffer(1, buf.length, context.sampleRate);
+                buffer.getChannelData(0).set(buf);
+                var source = context.createBufferSource();
+                source.buffer = buffer;
+                source.connect(context.destination);
+                source.start(0);
+            }
+
+            //
+            // Rx
+            //
+
+            captureStart.addEventListener("click", function () {
+                init();
+
+                let constraints = {
+                    audio: {
+                        // not sure if these are necessary to have
+                        echoCancellation: false,
+                        autoGainControl: false,
+                        noiseSuppression: false
+                    }
+                };
+
+                navigator.mediaDevices.getUserMedia(constraints).then(function (e) {
+                    mediaStream = context.createMediaStreamSource(e);
+
+                    var bufferSize = 16*1024;
+                    var numberOfInputChannels = 1;
+                    var numberOfOutputChannels = 1;
+
+                    if (context.createScriptProcessor) {
+                        recorder = context.createScriptProcessor(
+                                bufferSize,
+                                numberOfInputChannels,
+                                numberOfOutputChannels);
+                    } else {
+                        recorder = context.createJavaScriptNode(
+                                bufferSize,
+                                numberOfInputChannels,
+                                numberOfOutputChannels);
+                    }
+
+                    recorder.onaudioprocess = function (e) {
+                        var source = e.inputBuffer;
+                        var offlineCtx = new OfflineAudioContext(source.numberOfChannels, 48000*source.duration, 48000);
+                        var offlineSource = offlineCtx.createBufferSource();
+
+                        offlineSource.buffer = source;
+                        offlineSource.connect(offlineCtx.destination);
+                        offlineSource.start();
+                        offlineCtx.startRendering();
+                        offlineCtx.oncomplete = function(e) {
+                            var resampled = e.renderedBuffer.getChannelData(0);
+                            var res = ggwave.decode(instance, convertTypedArray(new Float32Array(resampled), Int8Array));
+                            if (res) {
+                                rxData.value = res;
+                            }
+                        };
+                    }
+
+                    mediaStream.connect(recorder);
+                    recorder.connect(context.destination);
+                }).catch(function (e) {
+                    console.error(e);
+                });
+
+                rxData.value = 'Listening ...';
+                captureStart.hidden = true;
+                captureStop.hidden = false;
+            });
+
+            captureStop.addEventListener("click", function () {
+                if (recorder) {
+                    recorder.disconnect(context.destination);
+                    mediaStream.disconnect(recorder);
+                }
+
+                rxData.value = 'Audio capture is paused! Press the "Start capturing" button to analyze audio from the microphone';
+                captureStart.hidden = false;
+                captureStop.hidden = true;
+            });
+
+            captureStop.click();
+        </script>
+    </body>
+</html>
--- a/examples/ggwave-to-file/main.cpp
+++ b/examples/ggwave-to-file/main.cpp
@@ -67,7 +67,6 @@ int main(int argc, char** argv) {
        return -3;
    }

-
    fprintf(stderr, "Generating waveform for message '%s' ...\n", message.c_str());

    GGWave ggWave({ GGWave::kBaseSampleRate, sampleRateOut, 1024, GGWAVE_SAMPLE_FORMAT_F32, GGWAVE_SAMPLE_FORMAT_I16 });
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,6 +1,17 @@
 if (EMSCRIPTEN)
+    #
+    # test-ggwave-js
+
+    set(TEST_TARGET test-ggwave-js)
+
+    add_test(NAME ${TEST_TARGET}
+        COMMAND node test-ggwave.js
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+        )
+
    return()
 endif()
+
 #
 # test-ggwave-c

--- a/tests/test-ggwave.js
+++ b/tests/test-ggwave.js
@@ -0,0 +1,19 @@
+var factory = require('../bindings/javascript/ggwave.js')
+
+factory().then(function(ggwave) {
+    // create ggwave instance with default parameters
+    var parameters = ggwave.getDefaultParameters();
+    var instance = ggwave.init(parameters);
+
+    var payload = 'hello js';
+
+    // generate audio waveform for string "hello js"
+    var waveform = ggwave.encode(instance, payload, ggwave.TxProtocolId.GGWAVE_TX_PROTOCOL_AUDIBLE_FAST, 10);
+
+    // decode the audio waveform back to text
+    var res = ggwave.decode(instance, waveform);
+
+    if (res != payload) {
+        process.exit(1);
+    }
+});
--- a/tests/test-ggwave.py
+++ b/tests/test-ggwave.py
@@ -1,6 +1,7 @@
 import sys
 import ggwave

+# create ggwave instance with default parameters
 instance = ggwave.init()

 payload = 'hello python'