Add execPath option (#9)

Author: ehmicky

index.d.ts

@@ -13,6 +13,15 @@ declare namespace npmRunPath {
 		Set it to an empty string to exclude the default PATH.
 		*/
 		readonly path?: string;
+
+		/**
+		Path to the Node.js executable to use in child processes if that is different from the current one. Its directory is pushed to the front of PATH.
+
+		This can be either an absolute path or a path relative to the `cwd` option.
+
+		@default process.execPath
+		*/
+		readonly execPath?: string;
 	}
 
 	interface ProcessEnv {
@@ -31,6 +40,15 @@ declare namespace npmRunPath {
 		Accepts an object of environment variables, like `process.env`, and modifies the PATH using the correct [PATH key](https://github.com/sindresorhus/path-key). Use this if you're modifying the PATH for use in the `child_process` options.
 		*/
 		readonly env?: ProcessEnv;
+
+		/**
+		Path to the current Node.js executable. Its directory is pushed to the front of PATH.
+
+		This can be either an absolute path or a path relative to the `cwd` option.
+
+		@default process.execPath
+		*/
+		readonly execPath?: string;
 	}
 }
 

index.js

@@ -6,6 +6,7 @@ const npmRunPath = options => {
 	options = {
 		cwd: process.cwd(),
 		path: process.env[pathKey()],
+		execPath: process.execPath,
 		...options
 	};
 
@@ -20,7 +21,8 @@ const npmRunPath = options => {
 	}
 
 	// Ensure the running `node` binary is used
-	result.unshift(path.dirname(process.execPath));
+	const execPathDir = path.resolve(options.cwd, options.execPath, '..');
+	result.unshift(execPathDir);
 
 	return result.concat(options.path).join(path.delimiter);
 };

index.test-d.ts

@@ -5,7 +5,9 @@ import {ProcessEnv} from '.';
 expectType<string>(npmRunPath());
 expectType<string>(npmRunPath({cwd: '/foo'}));
 expectType<string>(npmRunPath({path: '/usr/local/bin'}));
+expectType<string>(npmRunPath({execPath: '/usr/local/bin'}));
 
 expectType<ProcessEnv>(npmRunPath.env());
 expectType<ProcessEnv>(npmRunPath.env({cwd: '/foo'}));
 expectType<ProcessEnv>(npmRunPath.env({env: process.env}));
+expectType<ProcessEnv>(npmRunPath.env({execPath: '/usr/local/bin'}));

readme.md

@@ -56,6 +56,15 @@ Default: [`PATH`](https://github.com/sindresorhus/path-key)
 PATH to be appended.<br>
 Set it to an empty string to exclude the default PATH.
 
+##### execPath
+
+Type: `string`<br>
+Default: `process.execPath`
+
+Path to the current Node.js executable. Its directory is pushed to the front of PATH.
+
+This can be either an absolute path or a path relative to the [`cwd` option](#cwd).
+
 ### npmRunPath.env(options?)
 
 Returns the augmented [`process.env`](https://nodejs.org/api/process.html#process_process_env) object.
@@ -77,6 +86,15 @@ Type: `Object`
 
 Accepts an object of environment variables, like `process.env`, and modifies the PATH using the correct [PATH key](https://github.com/sindresorhus/path-key). Use this if you're modifying the PATH for use in the `child_process` options.
 
+##### execPath
+
+Type: `string`<br>
+Default: `process.execPath`
+
+Path to the Node.js executable to use in child processes if that is different from the current one. Its directory is pushed to the front of PATH.
+
+This can be either an absolute path or a path relative to the [`cwd` option](#cwd).
+
 
 ## Related
 

test.js

@@ -20,3 +20,17 @@ test('push `execPath` to the front of the PATH', t => {
 		path.dirname(process.execPath)
 	);
 });
+
+test('can change `execPath` with the `execPath` option', t => {
+	t.is(
+		npmRunPath({path: '', execPath: 'test/test'}).split(path.delimiter)[0],
+		path.resolve(process.cwd(), 'test')
+	);
+});
+
+test('the `execPath` option is relative to the `cwd` option', t => {
+	t.is(
+		npmRunPath({path: '', execPath: 'test/test', cwd: '/dir'}).split(path.delimiter)[0],
+		path.normalize('/dir/test')
+	);
+});