pkg: add type lints.

lib/backend.js

@@ -12,7 +12,12 @@ const features = require('./features');
  * Expose
  */
 
-if (features.HAS_ALL)
-  module.exports = require('./modern');
-else
-  module.exports = require('./legacy');
+if (features.HAS_ALL) {
+  const modern = require('./modern');
+
+  module.exports = modern;
+} else {
+  const legacy = require('./legacy');
+
+  module.exports = legacy;
+}

lib/compat.js

@@ -224,6 +224,10 @@ function mkdirpSync(dir, mode) {
   }
 }
 
+/**
+ * @returns {Array} [args, recursive]
+ */
+
 function mkdirArgs(path, options) {
   let mode = null;
   let recursive = false;
@@ -261,13 +265,24 @@ async function mkdir(path, options) {
   return call(fs.mkdir, args);
 }
 
+/**
+ * Synchronously creates a directory.
+ * @param {fs.PathLike} path
+ * @param {{
+ *   recursive?: boolean;
+ *   mode?: string | number;
+ *   } | number} [options]
+ * @returns {string | void}
+ */
+
 function mkdirSync(path, options) {
   const [args, recursive] = mkdirArgs(path, options);
 
   if (recursive)
     return mkdirpSync(...args);
 
-  return fs.mkdirSync(...args);
+  const [argPath, argMode] = args;
+  return fs.mkdirSync(argPath, argMode);
 }
 
 /*
@@ -281,11 +296,19 @@ async function open(...args) {
   return call(fs.open, args);
 }
 
-function openSync(...args) {
-  if (args[1] == null)
-    args[1] = 'r';
+/**
+ * Synchronously opens a file.
+ * @param {fs.PathLike} path
+ * @param {string | number} [flags]
+ * @param {string | number} [mode]
+ * @returns {number}
+ */
+
+function openSync(path, flags, mode) {
+  if (flags == null)
+    flags = 'r';
 
-  return fs.openSync(...args);
+  return fs.openSync(path, flags, mode);
 }
 
 /*
@@ -299,6 +322,7 @@ async function read(...args) {
 
 function readSync(...args) {
   args[1] = toBuffer(args[1]);
+  // @ts-ignore
   return fs.readSync(...args);
 }
 
@@ -330,6 +354,7 @@ async function readdir(...args) {
 function readdirSync(...args) {
   const [dir, options] = args;
   const withFileTypes = options && options.withFileTypes;
+  // @ts-ignore
   const list = fs.readdirSync(...args);
 
   if (!withFileTypes || fs.Dirent)
@@ -429,7 +454,9 @@ class Dir {
   _error() {
     const err = new Error('Directory handle was closed');
 
+    // @ts-ignore
     err.code = 'ERR_DIR_CLOSED';
+    // @ts-ignore
     err.name = `Error [${err.code}]`;
 
     if (Error.captureStackTrace)
@@ -524,12 +551,26 @@ realpath.native = async function(...args) {
   return call(fs.realpath, args);
 };
 
-function realpathSync(...args) {
-  return fs.realpathSync(...args);
+/**
+ * Returns the resolved pathname.
+ * @param {fs.PathLike} p
+ * @param {fs.EncodingOption} [options]
+ * @returns {string | Buffer}
+ */
+
+function realpathSync(p, options) {
+  return fs.realpathSync(p, options);
 }
 
-realpathSync.native = function(...args) {
-  return fs.realpathSync(...args);
+/**
+ * Returns the resolved pathname.
+ * @param {fs.PathLike} p
+ * @param {fs.EncodingOption} [options]
+ * @returns {string | Buffer}
+ */
+
+realpathSync.native = function(p, options) {
+  return fs.realpathSync(p, options);
 };
 
 /*
@@ -825,6 +866,7 @@ function writeSync(...args) {
   if (typeof args[1] !== 'string')
     args[1] = toBuffer(args[1]);
 
+  // @ts-ignore
   return fs.writeSync(...args);
 }
 
@@ -843,6 +885,7 @@ function writeFileSync(...args) {
   if (typeof args[1] !== 'string')
     args[1] = toBuffer(args[1]);
 
+  // @ts-ignore
   return fs.writeFileSync(...args);
 }
 

lib/error.js

@@ -38,6 +38,22 @@ class ArgError extends TypeError {
   }
 }
 
+/**
+ * TypeError w/ code.
+ */
+
+class TypeCodeError extends TypeError {
+  constructor(msg, code = '') {
+    super(msg);
+
+    this.code = code;
+    this.name = `TypeError [${this.code}]`;
+
+    if (Error.captureStackTrace)
+      Error.captureStackTrace(this, this.constructor);
+  }
+}
+
 /**
  * FSError
  */
@@ -143,3 +159,4 @@ FSError.EISDIR = {
 
 exports.ArgError = ArgError;
 exports.FSError = FSError;
+exports.TypeCodeError = TypeCodeError;