Fix polyfill of TextEncoder and TextDecoder

This commit does a few things, including:

* Fixing the generated JS of `wasm-bindgen` to allow polyfills to work.
  (a minor tweak of the generated JS)

* All examples are updated to include a Webpack-specific polyfill for
  these two types to get examples working in Edge.

* A new page has been added to the guide about supported browsers. This
  mentions known caveats like IE 11 requiring `wasm2js` as well as
  documenting some `TextEncoder` and `TextDecoder` workarounds for Edge.

Closes #895

crates/cli-support/src/js/mod.rs

@@ -972,7 +972,7 @@ impl<'a> Context<'a> {
             "
             function passStringToWasm(arg) {{
                 {}
-                const buf = cachedEncoder.encode(arg);
+                const buf = cachedTextEncoder.encode(arg);
                 const ptr = wasm.__wbindgen_malloc(buf.length);
                 getUint8Memory().set(buf, ptr);
                 return [ptr, buf.length];
@@ -1065,58 +1065,32 @@ impl<'a> Context<'a> {
         if !self.exposed_globals.insert("text_encoder") {
             return;
         }
-        if self.config.nodejs_experimental_modules {
-            self.imports
-                .push_str("import { TextEncoder } from 'util';\n");
-        } else if self.config.nodejs {
-            self.global(
-                "
-                const TextEncoder = require('util').TextEncoder;
-                ",
-            );
-        } else if !(self.config.browser || self.config.no_modules) {
-            self.global(
-                "
-                const TextEncoder = typeof self === 'object' && self.TextEncoder
-                    ? self.TextEncoder
-                    : require('util').TextEncoder;
-                ",
-            );
-        }
-        self.global(
-            "
-            let cachedEncoder = new TextEncoder('utf-8');
-            ",
-        );
+        self.expose_text_processor("TextEncoder");
     }
 
     fn expose_text_decoder(&mut self) {
         if !self.exposed_globals.insert("text_decoder") {
             return;
         }
+        self.expose_text_processor("TextDecoder");
+    }
+
+    fn expose_text_processor(&mut self, s: &str) {
         if self.config.nodejs_experimental_modules {
-            self.imports
-                .push_str("import { TextDecoder } from 'util';\n");
+            self.imports.push_str(&format!("import {{ {} }} from 'util';\n", s));
+            self.global(&format!("let cached{0} = new {0}('utf-8');", s));
         } else if self.config.nodejs {
-            self.global(
-                "
-                const TextDecoder = require('util').TextDecoder;
-                ",
-            );
+            self.global(&format!("const {0} = require('util').{0};", s));
+            self.global(&format!("let cached{0} = new {0}('utf-8');", s));
         } else if !(self.config.browser || self.config.no_modules) {
             self.global(
-                "
-                const TextDecoder = typeof self === 'object' && self.TextDecoder
-                    ? self.TextDecoder
-                    : require('util').TextDecoder;
-                ",
+                &format!("
+                    const l{0} = typeof {0} === 'undefined' ? \
+                        require('util').{0} : {0};\
+                ", s)
             );
+            self.global(&format!("let cached{0} = new l{0}('utf-8');", s));
         }
-        self.global(
-            "
-            let cachedDecoder = new TextDecoder('utf-8');
-            ",
-        );
     }
 
     fn expose_get_string_from_wasm(&mut self) {
@@ -1148,7 +1122,7 @@ impl<'a> Context<'a> {
         self.global(&format!(
             "
             function getStringFromWasm(ptr, len) {{
-                return cachedDecoder.decode(getUint8Memory().{}(ptr, ptr + len));
+                return cachedTextDecoder.decode(getUint8Memory().{}(ptr, ptr + len));
             }}
         ",
             method

examples/add/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/add/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -8,7 +9,13 @@ module.exports = {
         filename: 'index.js',
     },
     plugins: [
-        new HtmlWebpackPlugin()
+        new HtmlWebpackPlugin(),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
+        })
     ],
     mode: 'development'
 };

examples/canvas/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/canvas/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/char/package.json

@@ -1,11 +1,13 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
-    "webpack": "^4.8.3",
+    "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",
-    "webpack-dev-server": "^3.1.4"
+    "webpack-dev-server": "^3.1.0"
   }
 }

examples/char/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/closures/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/closures/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/console_log/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/console_log/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/dom/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/dom/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/duck-typed-interfaces/package.json

@@ -1,8 +1,11 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
+    "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",
     "webpack-dev-server": "^3.1.0"

examples/duck-typed-interfaces/webpack.config.js

@@ -1,4 +1,6 @@
 const path = require('path');
+const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -6,5 +8,14 @@ module.exports = {
         path: path.resolve(__dirname, 'dist'),
         filename: 'index.js',
     },
+    plugins: [
+        new HtmlWebpackPlugin(),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
+        })
+    ],
     mode: 'development'
 };

examples/fetch/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/fetch/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -8,7 +9,13 @@ module.exports = {
         filename: 'index.js',
     },
     plugins: [
-        new HtmlWebpackPlugin()
+        new HtmlWebpackPlugin(),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
+        })
     ],
     mode: 'development'
 };

examples/guide-supported-types-examples/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/guide-supported-types-examples/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -8,7 +9,13 @@ module.exports = {
         filename: 'index.js',
     },
     plugins: [
-        new HtmlWebpackPlugin()
+        new HtmlWebpackPlugin(),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
+        })
     ],
     mode: 'development'
 };

examples/hello_world/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/hello_world/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -8,7 +9,13 @@ module.exports = {
         filename: 'index.js',
     },
     plugins: [
-        new HtmlWebpackPlugin()
+        new HtmlWebpackPlugin(),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
+        })
     ],
     mode: 'development'
 };

examples/import_js/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/import_js/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/julia_set/package.json

@@ -1,10 +1,12 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
-    "webpack": "^4.0.1",
+    "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",
     "webpack-dev-server": "^3.1.0"
   }

examples/julia_set/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,10 +11,13 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
-    mode: 'development',
-    devServer: {
-        open: true
-    }
+    mode: 'development'
 };

examples/paint/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/paint/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/performance/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/performance/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/wasm-in-wasm/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/wasm-in-wasm/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/wasm2js/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/wasm2js/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/webaudio/package.json

@@ -1,10 +1,12 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
-    "webpack": "^4.16.5",
+    "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",
     "webpack-dev-server": "^3.1.0"
   }

examples/webaudio/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

examples/webgl/package.json

@@ -1,8 +1,10 @@
 {
   "scripts": {
+    "build": "webpack",
     "serve": "webpack-dev-server"
   },
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.11.1",
     "webpack-cli": "^3.1.1",

examples/webgl/webpack.config.js

@@ -1,5 +1,6 @@
 const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const webpack = require('webpack');
 
 module.exports = {
     entry: './index.js',
@@ -10,6 +11,12 @@ module.exports = {
     plugins: [
         new HtmlWebpackPlugin({
             template: "index.html"
+        }),
+        // Have this example work in Edge which doesn't ship `TextEncoder` or
+        // `TextDecoder` at this time.
+        new webpack.ProvidePlugin({
+          TextDecoder: ['text-encoding', 'TextDecoder'],
+          TextEncoder: ['text-encoding', 'TextEncoder']
         })
     ],
     mode: 'development'

guide/src/SUMMARY.md

@@ -38,6 +38,7 @@
   - [Command Line Interface](./reference/cli.md)
   - [Optimizing for Size](./reference/optimize-size.md)
   - [Supported Rust Targets](./reference/rust-targets.md)
+  - [Supported Browsers](./reference/browser-support.md)
   - [Supported Types](./reference/types.md)
     - [Imported JavaScript Types](./reference/types/imported-js-types.md)
     - [Exported Rust Types](./reference/types/exported-rust-types.md)

guide/src/reference/browser-support.md

@@ -0,0 +1,61 @@
+# Supported Browsers
+
+The output of `wasm-bindgn` includes a JS file, and as a result it's good to
+know what browsers that file is expected to be used in! By default the output
+uses ES modules which isn't implemented in all browsers today, but when using a
+bundler (like Webpack) you should be able to produce output suitable for all
+browsers.
+
+Firefox, Chrome, Safari, and Edge browsers are all supported by
+`wasm-bindgen`. If you find a problem in one of these browsers please [report
+it] as we'd like to fix the bug! If you find a bug in another browser we would
+also like to be aware of it!
+
+## Caveats
+
+* **IE 11** - `wasm-bindgen` by default requires support for
+  `WebAssembly`, but no version of IE currently supports `WebAssembly`. You can
+  support IE by [compiling wasm files to JS using `wasm2js`][w2js] (you can [see
+  an example of doing this too](../examples/wasm2js.html)). Note
+  that at this time no bundler will do this by default, but we'd love to
+  document plugins which do this if you are aware of one!
+
+* **Edge** - the `TextEncoder` and `TextDecoder` APIs are not currently
+  available in Edge which `wasm-bindgen` uses to encode/decode strings between
+  JS and Rust. You can polyfill this with at least one of two strategies:
+
+  1. If using a bundler, you can likely configure the bundler to polyfill these
+     types by default. For example if you're using Webpack you can use the
+     [`ProvidePlugin` interface][wpp] like so after also adding
+     [`text-encoding`] to your `package.json`
+
+     ```js
+     const webpack = require('webpack');
+
+     module.exports = {
+         plugins: [
+             new webpack.ProvidePlugin({
+               TextDecoder: ['text-encoding', 'TextDecoder'],
+               TextEncoder: ['text-encoding', 'TextEncoder']
+             })
+         ]
+
+         // ... other configuration options
+     };
+     ```
+
+  2. If you're not using a bundler you can also include support manually by
+     adding a `<script>` tag which defines the `TextEncoder` and `TextDecoder`
+     globals. [This StackOverflow question][soq] has some example usage and MDN
+     has a [`TextEncoder` polyfill implementation][mdntepi] to get you started
+     as well.
+
+If you find other incompatibilities please report them to us! We'd love to
+either keep this list up-to-date or fix the underlying bugs :)
+
+[report it]: https://github.com/rustwasm/wasm-bindgen/issues/new
+[w2js]: https://github.com/WebAssembly/binaryen
+[wpp]: https://webpack.js.org/plugins/provide-plugin/
+[`text-encoding`]: https://www.npmjs.com/package/text-encoding
+[soq]: https://stackoverflow.com/questions/40662142/polyfill-for-textdecoder/46549188#46549188
+[mdntepi]: https://developer.mozilla.org/en-US/docs/Web/API/TextEncoder#Polyfill

package.json

@@ -1,6 +1,7 @@
 {
   "license": "MIT",
   "devDependencies": {
+    "text-encoding": "^0.7.0",
     "html-webpack-plugin": "^3.2.0",
     "webpack": "^4.17.1",
     "webpack-cli": "^3.1.1",