chore: simplify default function for path context

Author: blakebyrnes

README.md

@@ -141,8 +141,7 @@ Unlike `VM`, `NodeVM` allows you to require modules in the same way that you wou
 * `require.builtin` - Array of allowed built-in modules, accepts ["\*"] for all (default: none). **WARNING**: "\*" can be dangerous as new built-ins can be added.
 * `require.root` - Restricted path(s) where local modules can be required (default: every path).
 * `require.mock` - Collection of mock modules (both external or built-in).
-* `require.context` - `host` (default) to require modules in the host and proxy them into the sandbox. `sandbox` to load, compile, and require modules in the sandbox. Except for `events`, built-in modules are always required in the host and proxied into the sandbox.
-* `require.pathContext` - A callback allowing custom context to be determined per module. Parameters are the module name, and extension. The callback must return `host` or `sandbox` as per above.
+* `require.context` - `host` (default) to require modules in the host and proxy them into the sandbox. `sandbox` to load, compile, and require modules in the sandbox. `callback(moduleFilename, ext)` to dynamically choose a context per module. The default will be sandbox is nothing is specified. Except for `events`, built-in modules are always required in the host and proxied into the sandbox.
 * `require.import` - An array of modules to be loaded into NodeVM on start.
 * `require.resolve` - An additional lookup function in case a module wasn't found in one of the traditional node lookup paths.
 * `require.customRequire` - Use instead of the `require` function to load modules from the host.

lib/nodevm.js

@@ -24,7 +24,7 @@
  *
  * @callback pathContextCallback
  * @param {string} modulePath - The full path to the module filename being requested.
- * @param {string} extensionType - The type of extension (node, js, json)
+ * @param {string} extensionType - The module type (node = native, js = cjs/esm module)
  * @return {("host"|"sandbox")} The context for this module.
  */
 

lib/resolver-compat.js

@@ -113,7 +113,7 @@ class LegacyResolver extends DefaultResolver {
 	loadJS(vm, mod, filename) {
 		filename = this.pathResolve(filename);
 		this.checkAccess(mod, filename);
-		if (this.pathContext(filename, 'js') === 'sandbox') {
+		if (this.pathContext(filename, 'js') !== 'host') {
 			const trustedMod = this.trustedMods.get(mod);
 			const script = this.readScript(filename);
 			vm.run(script, {filename, strict: true, module: mod, wrapper: 'none', dirname: trustedMod ? trustedMod.path : mod.path});
@@ -332,7 +332,7 @@ function resolverFromOptions(vm, options, override, compiler) {
 		};
 	}
 
-	const pathContext = typeof options.context === 'function' ? ((module, ext) => options.context(module, ext) || 'sandbox') : (() => context);
+	const pathContext = typeof context === 'function' ? context : (() => context);
 
 	if (typeof externalOpt !== 'object') {
 		return new DefaultResolver(fsOpt, builtins, checkPath, [], pathContext, newCustomResolver, hostRequire, compiler, strict);

lib/resolver.js

@@ -197,7 +197,7 @@ class DefaultResolver extends Resolver {
 	loadJS(vm, mod, filename) {
 		filename = this.pathResolve(filename);
 		this.checkAccess(mod, filename);
-		if (this.pathContext(filename, 'js') === 'sandbox') {
+		if (this.pathContext(filename, 'js') !== 'host') {
 			const script = this.readScript(filename);
 			vm.run(script, {filename, strict: this.strict, module: mod, wrapper: 'none', dirname: mod.path});
 		} else {
@@ -216,7 +216,7 @@ class DefaultResolver extends Resolver {
 	loadNode(vm, mod, filename) {
 		filename = this.pathResolve(filename);
 		this.checkAccess(mod, filename);
-		if (this.pathContext(filename, 'node') === 'sandbox') throw new VMError('Native modules can be required only with context set to \'host\'.');
+		if (this.pathContext(filename, 'node') !== 'host') throw new VMError('Native modules can be required only with context set to \'host\'.');
 		const m = this.hostRequire(filename);
 		mod.exports = vm.readonly(m);
 	}