Fix handling of tilde in npm prefix path

sindresorhus · sindresorhus · commit 1d742094eae2 · 2026-02-02T17:13:15.000+07:00
Fixes #21
diff --git a/index.js b/index.js
@@ -6,6 +6,8 @@ import ini from 'ini';
 
 const isWindows = process.platform === 'win32';
 
+const untildify = pathWithTilde => pathWithTilde && pathWithTilde.startsWith('~') ? path.join(os.homedir(), pathWithTilde.slice(1)) : pathWithTilde;
+
 const readRc = filePath => {
 	try {
 		return ini.parse(fs.readFileSync(filePath, 'utf8')).prefix;
@@ -69,7 +71,7 @@ const getNpmPrefix = () => {
 	return getDefaultNpmPrefix();
 };
 
-const npmPrefix = path.resolve(getNpmPrefix());
+const npmPrefix = path.resolve(untildify(getNpmPrefix()));
 
 const getYarnHomeDirectory = () => {
 	if (process.getuid?.() === 0 && !process.env.FAKEROOTKEY) {
diff --git a/test.js b/test.js
@@ -62,6 +62,26 @@ test.serial('yarn with PREFIX', async t => {
 	delete process.env.PREFIX;
 });
 
+test.serial('npm.prefix expands tilde in prefix', async t => {
+	const savedKeys = Object.keys(process.env).filter(name => name.toLowerCase() === 'npm_config_prefix');
+	const savedValues = Object.fromEntries(savedKeys.map(key => [key, process.env[key]]));
+
+	for (const key of savedKeys) {
+		delete process.env[key];
+	}
+
+	// eslint-disable-next-line camelcase
+	process.env.npm_config_prefix = '~/.npm-global';
+	const {default: globalDirectory} = await importFresh('./index.js');
+	t.is(globalDirectory.npm.prefix, path.join(os.homedir(), '.npm-global'));
+	t.false(globalDirectory.npm.prefix.includes('~'));
+	delete process.env.npm_config_prefix;
+
+	for (const [key, value] of Object.entries(savedValues)) {
+		process.env[key] = value;
+	}
+});
+
 test.serial('reload package and get npm.prefix with env', async t => {
 	const savedKeys = Object.keys(process.env).filter(name => name.toLowerCase() === 'npm_config_prefix');
 	const savedValues = Object.fromEntries(savedKeys.map(key => [key, process.env[key]]));
