103 lines
4.9 KiB
Markdown
103 lines
4.9 KiB
Markdown
# WebAssembly Feature Detection
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A small library to detect which features of WebAssembly are supported.
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- ✅ Runs in browsers, Node and Deno
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- ✅ Tree-shakable (only bundle the detectors you use)
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- ✅ Provided as an ES6, CommonJS and UMD module.
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- ✅ CSP compatible
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- ✅ All detectors add up to only ~670B gzipped
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## Installation
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```
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npm install -g wasm-feature-detect
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```
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## Usage
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```html
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<script type="module">
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import { simd } from "wasm-feature-detect";
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if (await simd()) {
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/* SIMD support */
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} else {
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/* No SIMD support */
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}
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</script>
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```
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### Hotlinking from Unpkg
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```html
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<script type="module">
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import { simd } from "https://unpkg.com/wasm-feature-detect?module";
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// ...
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</script>
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```
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If required, there’s also a UMD version
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```html
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<script src="https://unpkg.com/wasm-feature-detect/dist/umd/index.js"></script>
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<script>
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if (await wasmFeatureDetect.simd()) {
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// ...
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}
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</script>
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```
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## Detectors
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All detectors return a `Promise<bool>`.
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| Function | Proposal |
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| ------------------------ | ------------------------------------------------------------------------------------------------------------ |
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| `bigInt()` | [BigInt integration](https://github.com/WebAssembly/JS-BigInt-integration) |
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| `bulkMemory()` | [Bulk memory operations](https://github.com/webassembly/bulk-memory-operations) |
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| `exceptions()` | [Exception handling](https://github.com/WebAssembly/exception-handling) |
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| `extendedConst()` | [Extented Const Expressesions](https://github.com/WebAssembly/extended-const) |
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| `gc()` | [Garbage Collection](https://github.com/WebAssembly/gc) |
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| `memory64()` | [Memory64](https://github.com/WebAssembly/memory64) |
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| `multiValue()` | [Multi-value](https://github.com/WebAssembly/multi-value) |
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| `mutableGlobals()` | [Importable/Exportable mutable globals]() |
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| `referenceTypes()` | [Reference Types](https://github.com/WebAssembly/reference-types) |
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| `relaxedSimd()` | [Relaxed SIMD](https://github.com/webassembly/relaxed-simd) |
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| `saturatedFloatToInt()` | [Non-trapping float-to-int conversions](https://github.com/WebAssembly/nontrapping-float-to-int-conversions) |
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| `signExtensions()` | [Sign-extension operators](https://github.com/WebAssembly/sign-extension-ops) |
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| `simd()` | [Fixed-Width SIMD](https://github.com/webassembly/simd) |
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| `streamingCompilation()` | [Streaming Compilation](https://webassembly.github.io/spec/web-api/index.html#streaming-modules) |
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| `tailCall()` | [Tail call](https://github.com/webassembly/tail-call) |
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| `threads()` | [Threads](https://github.com/webassembly/threads) |
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## Why are all the tests async?
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The _technical_ reason is that some tests might have to be augmented to be asynchronous in the future. For example, Firefox is planning to [make a change][ff coop] that would require a `postMessage` call to detect SABs, which are required for threads.
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The _other_ reason is that you _should_ be using `WebAssembly.compile`, `WebAssembly.instantiate`, or their streaming versions `WebAssembly.compileStreaming` and `WebAssembly.instantiateStreaming`, which are all asynchronous. You should already be prepared for asynchronous code when using WebAssembly!
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## Contributing
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If you want to contribute a new feature test, all you need to do is create a new folder in `src/detectors` and it will be automatically picked up. The folder may contain a `module.wat` file, which will be compiled using [`wabt.js`](https://github.com/AssemblyScript/wabt.js).
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```wat
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;; Name: <Name of the feature for the README>
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;; Proposal: <Link to the proposal’s explainer/repo>
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;; Features: <Space-separated list of WasmFeatures from wabt.js>
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(module
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;; More WAT code here
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)
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```
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The folder can also contain an optional `index.js` file, whose default export must be an async function. This function can do additional testing in JavaScript and must return a boolean. See the “threads” detector as an example.
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It must contain at least one of `module.wat` or `index.js`.
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[ff coop]: https://groups.google.com/forum/#!msg/mozilla.dev.platform/IHkBZlHETpA/dwsMNchWEQAJ
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[wat2wasm]: https://github.com/webassembly/wabt
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---
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License Apache-2.0
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