moved to using cargo init instead of copying Cargo.toml

Author: thomashorrobin

packages/react-scripts/package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-scripts-rust",
-  "version": "2.0.16",
+  "version": "2.0.17",
   "description": "Configuration and scripts for using Rust with Create React App",
   "repository": "thomashorrobin/create-react-app-rust",
   "license": "MIT",
@@ -65,6 +65,7 @@
     "sass-loader": "7.1.0",
     "style-loader": "0.23.0",
     "terser-webpack-plugin": "1.1.0",
+    "toml-js": "0.0.8",
     "url-loader": "1.1.1",
     "wasm-loader": "^1.3.0",
     "webpack": "4.19.1",

packages/react-scripts/scripts/utils/rustUtils.js

@@ -1,6 +1,8 @@
 const execSync = require('child_process').execSync;
 const chalk = require('chalk');
 const commandExistsSync = require('command-exists').sync;
+const fs = require('fs');
+const toml = require('toml-js');
 
 module.exports = {
   build: () => {
@@ -23,6 +25,17 @@ module.exports = {
         console.log(`${chalk.bold.red('error installing wasm-gc')} please install manually ${chalk.red('cargo install wasm-gc')}')`);
       }
     }
+    execSync(
+      'cargo init --lib',
+      { stdio: 'inherit' }
+    );
+    fs.readFile('Cargo.toml', function (err, data) {
+        var cargo = toml.parse(data);
+        cargo.lib = {};
+        cargo.lib['crate-type'] = ['cdylib'];
+        cargo.lib.path = 'src/App.rs';
+        fs.writeFile('Cargo.toml', toml.dump(cargo), err => console.log(err));
+    });
     execSync(
       'rustup target add wasm32-unknown-unknown --toolchain nightly',
       { stdio: 'inherit' }