fix(NODE-4211): Do not require crypto in browser builds (#500)

package.json

@@ -43,6 +43,7 @@
     "@rollup/plugin-commonjs": "^15.0.0",
     "@rollup/plugin-json": "^4.1.0",
     "@rollup/plugin-node-resolve": "^9.0.0",
+    "@rollup/plugin-replace": "^4.0.0",
     "@rollup/plugin-typescript": "^6.0.0",
     "@typescript-eslint/eslint-plugin": "^3.10.1",
     "@typescript-eslint/parser": "^3.10.1",

rollup.config.js

@@ -5,6 +5,7 @@ import { nodeResolve } from '@rollup/plugin-node-resolve';
 import { babel } from '@rollup/plugin-babel';
 import typescript from '@rollup/plugin-typescript';
 import nodeGlobals from 'rollup-plugin-node-globals';
+import replace from '@rollup/plugin-replace';
 
 const tsConfig = {
   allowJs: false,
@@ -33,18 +34,26 @@ const tsConfig = {
 };
 const input = 'src/bson.ts';
 
-const plugins = [
-  typescript(tsConfig),
-  nodeResolve({ preferBuiltins: false }),
-  nodeBuiltins(),
-  nodeGlobals(),
-  commonjs({ extensions: ['.js', '.ts'] }),
-  babel({
-    babelHelpers: 'external',
-    plugins: ['@babel/plugin-external-helpers'],
-    presets: [['@babel/env', { modules: false }]]
-  })
-];
+const plugins = (options = { browser: false }) => {
+  return [
+    typescript(tsConfig),
+    nodeResolve({ preferBuiltins: false }),
+    nodeBuiltins(),
+    nodeGlobals(),
+    replace({
+      preventAssignment: true,
+      values: {
+        'process.browser': options.browser
+      }
+    }),
+    commonjs({ extensions: ['.js', '.ts'] }),
+    babel({
+      babelHelpers: 'external',
+      plugins: ['@babel/plugin-external-helpers'],
+      presets: [['@babel/env', { modules: false }]]
+    })
+  ];
+};
 
 const external = Object.keys(pkg.dependencies || {});
 
@@ -60,7 +69,7 @@ module.exports = [
       exports: 'named',
       sourcemap: true
     },
-    plugins,
+    plugins: plugins(),
     external
   },
   {
@@ -88,6 +97,6 @@ module.exports = [
         sourcemap: true
       }
     ],
-    plugins
+    plugins: plugins({ browser: true })
   }
 ];

src/parser/utils.ts

@@ -34,32 +34,38 @@ declare let require: Function;
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 declare let global: any;
 declare const self: unknown;
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+declare let process: any; // Used by @rollup/plugin-replace
 
 const detectRandomBytes = (): RandomBytesFunction => {
-  if (typeof window !== 'undefined') {
-    // browser crypto implementation(s)
-    const target = window.crypto || window.msCrypto; // allow for IE11
-    if (target && target.getRandomValues) {
-      return size => target.getRandomValues(Buffer.alloc(size));
+  if (process.browser) {
+    if (typeof window !== 'undefined') {
+      // browser crypto implementation(s)
+      const target = window.crypto || window.msCrypto; // allow for IE11
+      if (target && target.getRandomValues) {
+        return size => target.getRandomValues(Buffer.alloc(size));
+      }
     }
-  }
 
-  if (typeof global !== 'undefined' && global.crypto && global.crypto.getRandomValues) {
-    // allow for RN packages such as https://www.npmjs.com/package/react-native-get-random-values to populate global
-    return size => global.crypto.getRandomValues(Buffer.alloc(size));
-  }
+    if (typeof global !== 'undefined' && global.crypto && global.crypto.getRandomValues) {
+      // allow for RN packages such as https://www.npmjs.com/package/react-native-get-random-values to populate global
+      return size => global.crypto.getRandomValues(Buffer.alloc(size));
+    }
 
-  let requiredRandomBytes: RandomBytesFunction | null | undefined;
-  try {
-    // eslint-disable-next-line @typescript-eslint/no-var-requires
-    requiredRandomBytes = require('crypto').randomBytes;
-  } catch (e) {
-    // keep the fallback
-  }
+    return insecureRandomBytes;
+  } else {
+    let requiredRandomBytes: RandomBytesFunction | null | undefined;
+    try {
+      // eslint-disable-next-line @typescript-eslint/no-var-requires
+      requiredRandomBytes = require('crypto').randomBytes;
+    } catch (e) {
+      // keep the fallback
+    }
 
-  // NOTE: in transpiled cases the above require might return null/undefined
+    // NOTE: in transpiled cases the above require might return null/undefined
 
-  return requiredRandomBytes || insecureRandomBytes;
+    return requiredRandomBytes || insecureRandomBytes;
+  }
 };
 
 export const randomBytes = detectRandomBytes();