# TensorFlow.js

TensorFlow.js is an open-source hardware-accelerated JavaScript library for
training and deploying machine learning models.

> :warning: We recently released **TensorFlow.js 2.0**. If you have been using TensorFlow.js
> via a script tag without specifying a version and see an error saying no backends
> are found, then you should read our [release notes](https://github.com/tensorflow/tfjs/releases/tag/tfjs-v2.0.0)
> for instructions on how to upgrade.


**Develop ML in the Browser** <br/>
Use flexible and intuitive APIs to build models from scratch using the low-level
JavaScript linear algebra library or the high-level layers API.

**Develop ML in Node.js** <br/>
Execute native TensorFlow with the same TensorFlow.js API under the Node.js
runtime.

**Run Existing models** <br/>
Use TensorFlow.js model converters to run pre-existing TensorFlow models right
in the browser.

**Retrain Existing models** <br/>
Retrain pre-existing ML models using sensor data connected to the browser or
other client-side data.

## About this repo

This repository contains the logic and scripts that combine
several packages.

APIs:
- [TensorFlow.js Core](/tfjs-core),
  a flexible low-level API for neural networks and numerical computation.
- [TensorFlow.js Layers](/tfjs-layers),
  a high-level API which implements functionality similar to
  [Keras](https://keras.io/).
- [TensorFlow.js Data](/tfjs-data),
  a simple API to load and prepare data analogous to
  [tf.data](https://www.tensorflow.org/guide/datasets).
- [TensorFlow.js Converter](/tfjs-converter),
  tools to import a TensorFlow SavedModel to TensorFlow.js
- [TensorFlow.js Vis](/tfjs-vis),
  in-browser visualization for TensorFlow.js models
- [TensorFlow.js AutoML](/tfjs-automl),
  Set of APIs to load and run models produced by
  [AutoML Edge](https://cloud.google.com/vision/automl/docs/edge-quickstart).


Backends/Platforms:
- [TensorFlow.js CPU Backend](/tfjs-backend-cpu), pure-JS backend for Node.js and the browser.
- [TensorFlow.js WebGL Backend](/tfjs-backend-webgl), WebGL backend for the browser.
- [TensorFlow.js WASM Backend](/tfjs-backend-wasm), WebAssembly backend for the browser.
- [TensorFlow.js WebGPU](/tfjs-backend-webgpu), WebGPU backend for the browser.
- [TensorFlow.js Node](/tfjs-node), Node.js platform via TensorFlow C++ adapter.
- [TensorFlow.js React Native](/tfjs-react-native), React Native platform via expo-gl adapter.

If you care about bundle size, you can import those packages individually.

If you are looking for Node.js support, check out the [TensorFlow.js Node directory](/tfjs-node).

## Examples

Check out our
[examples repository](https://github.com/tensorflow/tfjs-examples)
and our [tutorials](https://js.tensorflow.org/tutorials/).

## Gallery

Be sure to check out [the gallery](GALLERY.md) of all projects related to TensorFlow.js.

## Pre-trained models

Be sure to also check out our [models repository](https://github.com/tensorflow/tfjs-models) where we host pre-trained models
on NPM.

## Benchmarks

[Benchmark tool](https://tensorflow.github.io/tfjs/e2e/benchmarks/local-benchmark/index.html). Use this webpage tool to test the performance related metrics (speed, memory, power, etc) of TensorFlow.js models on your local device with CPU, WebGL or WASM backend. You can benchmark custom models following this [guide](https://github.com/tensorflow/tfjs/blob/master/e2e/benchmarks/local-benchmark/README.md).

## Getting started

There are two main ways to get TensorFlow.js in your JavaScript project:
via <a href="https://developer.mozilla.org/en-US/docs/Learn/HTML/Howto/Use_JavaScript_within_a_webpage" target="_blank">script tags</a> <strong>or</strong> by installing it from <a href="https://www.npmjs.com/" target="_blank">NPM</a>
and using a build tool like <a href="https://parceljs.org/" target="_blank">Parcel</a>,
<a href="https://webpack.js.org/" target="_blank">WebPack</a>, or <a href="https://rollupjs.org/guide/en" target="_blank">Rollup</a>.

### via Script Tag

Add the following code to an HTML file:

```html
<html>
  <head>
    <!-- Load TensorFlow.js -->
    <script src="https://cdn.jsdelivr.net/npm/@tensorflow/tfjs/dist/tf.min.js"> </script>


    <!-- Place your code in the script tag below. You can also use an external .js file -->
    <script>
      // Notice there is no 'import' statement. 'tf' is available on the index-page
      // because of the script tag above.

      // Define a model for linear regression.
      const model = tf.sequential();
      model.add(tf.layers.dense({units: 1, inputShape: [1]}));

      // Prepare the model for training: Specify the loss and the optimizer.
      model.compile({loss: 'meanSquaredError', optimizer: 'sgd'});

      // Generate some synthetic data for training.
      const xs = tf.tensor2d([1, 2, 3, 4], [4, 1]);
      const ys = tf.tensor2d([1, 3, 5, 7], [4, 1]);

      // Train the model using the data.
      model.fit(xs, ys).then(() => {
        // Use the model to do inference on a data point the model hasn't seen before:
        // Open the browser devtools to see the output
        model.predict(tf.tensor2d([5], [1, 1])).print();
      });
    </script>
  </head>

  <body>
  </body>
</html>
```

Open up that HTML file in your browser, and the code should run!

### via NPM

Add TensorFlow.js to your project using <a href="https://yarnpkg.com/en/" target="_blank">yarn</a> <em>or</em> <a href="https://docs.npmjs.com/cli/npm" target="_blank">npm</a>. <b>Note:</b> Because
we use ES2017 syntax (such as `import`), this workflow assumes you are using a modern browser or a bundler/transpiler
to convert your code to something older browsers understand. See our
<a href='https://github.com/tensorflow/tfjs-examples' target="_blank">examples</a>
to see how we use <a href="https://parceljs.org/" target="_blank">Parcel</a> to build
our code. However, you are free to use any build tool that you prefer.



```js
import * as tf from '@tensorflow/tfjs';

// Define a model for linear regression.
const model = tf.sequential();
model.add(tf.layers.dense({units: 1, inputShape: [1]}));

// Prepare the model for training: Specify the loss and the optimizer.
model.compile({loss: 'meanSquaredError', optimizer: 'sgd'});

// Generate some synthetic data for training.
const xs = tf.tensor2d([1, 2, 3, 4], [4, 1]);
const ys = tf.tensor2d([1, 3, 5, 7], [4, 1]);

// Train the model using the data.
model.fit(xs, ys).then(() => {
  // Use the model to do inference on a data point the model hasn't seen before:
  model.predict(tf.tensor2d([5], [1, 1])).print();
});
```

See our <a href="https://js.tensorflow.org/tutorials/" target="_blank">tutorials</a>, <a href="https://github.com/tensorflow/tfjs-examples" target="_blank">examples</a>
and <a href="https://js.tensorflow.org/api/latest/">documentation</a> for more details.

## Importing pre-trained models

We support porting pre-trained models from:
- [TensorFlow SavedModel](https://github.com/tensorflow/tfjs-converter)
- [Keras](https://js.tensorflow.org/tutorials/import-keras.html)

## Find out more

[TensorFlow.js](https://js.tensorflow.org) is a part of the
[TensorFlow](https://www.tensorflow.org) ecosystem. For more info:
- For help from the community, use [`tensorflow.js`](https://stackoverflow.com/questions/tagged/tensorflow.js) tag on Stack Overflow.
- [js.tensorflow.org](https://js.tensorflow.org)
- [Tutorials](https://js.tensorflow.org/tutorials)
- [API reference](https://js.tensorflow.org/api/latest/)
- [Discussion mailing list](https://groups.google.com/a/tensorflow.org/forum/#!forum/tfjs)
- [TensorFlow.js Blog](https://blog.tensorflow.org/search?label=TensorFlow.js)

Thanks, <a href="https://www.browserstack.com/">BrowserStack</a>, for providing testing support.
