Node.js file stats

Every file comes with a set of details that we can inspect using Node.js. In particular, using the stat() method provided by the fs module.

You call it passing a file path, and once Node.js gets the file details it will call the callback function you pass, with 2 parameters: an error message, and the file stats:

const module "node:fs"fs = var require: NodeJS.Require
(id: string) => anyrequire('node:fs');

module "node:fs"fs.function stat(path: fs.PathLike, callback: (err: NodeJS.ErrnoException | null, stats: fs.Stats) => void): void (+3 overloads)stat('/Users/joe/test.txt', (err: NodeJS.ErrnoException | nullerr, stats: fs.Statsstats) => {
  if (err: NodeJS.ErrnoException | nullerr) {
    var console: Consoleconsole.Console.error(message?: any, ...optionalParams: any[]): void (+1 overload)error(err: NodeJS.ErrnoExceptionerr);
  }
  // we have access to the file stats in `stats`
});

Node.js also provides a sync method, which blocks the thread until the file stats are ready:

const module "node:fs"fs = var require: NodeJS.Require
(id: string) => anyrequire('node:fs');

try {
  const const stats: fs.Statsstats = module "node:fs"fs.const statSync: fs.StatSyncFn
(path: fs.PathLike, options?: undefined) => fs.Stats (+6 overloads)statSync('/Users/joe/test.txt');
} catch (var err: unknownerr) {
  var console: Consoleconsole.Console.error(message?: any, ...optionalParams: any[]): void (+1 overload)error(var err: unknownerr);
}

The file information is included in the stats variable. What kind of information can we extract using the stats?

A lot, including:

if the file is a directory or a file, using stats.isFile() and stats.isDirectory()
if the file is a symbolic link using stats.isSymbolicLink()
the file size in bytes using stats.size.

There are other advanced methods, but the bulk of what you'll use in your day-to-day programming is this.

const module "node:fs"fs = var require: NodeJS.Require
(id: string) => anyrequire('node:fs');

module "node:fs"fs.function stat(path: fs.PathLike, callback: (err: NodeJS.ErrnoException | null, stats: fs.Stats) => void): void (+3 overloads)stat('/Users/joe/test.txt', (err: NodeJS.ErrnoException | nullerr, stats: fs.Statsstats) => {
  if (err: NodeJS.ErrnoException | nullerr) {
    var console: Consoleconsole.Console.error(message?: any, ...optionalParams: any[]): void (+1 overload)error(err: NodeJS.ErrnoExceptionerr);
    return;
  }

  stats: fs.Statsstats.StatsBase<number>.isFile(): booleanisFile(); // true
  stats: fs.Statsstats.StatsBase<number>.isDirectory(): booleanisDirectory(); // false
  stats: fs.Statsstats.StatsBase<number>.isSymbolicLink(): booleanisSymbolicLink(); // false
  var console: Consoleconsole.Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)log(stats: fs.Statsstats.StatsBase<number>.size: numbersize); // 1024000 //= 1MB
});

You can also use promise-based fsPromises.stat() method offered by the fs/promises module if you like:

const module "node:fs/promises"fs = var require: NodeJS.Require
(id: string) => anyrequire('node:fs/promises');

async function function example(): Promise<void>example() {
  try {
    const const stats: Statsstats = await module "node:fs/promises"fs.function stat(path: PathLike, opts?: StatOptions & {
    bigint?: false | undefined;
}): Promise<Stats> (+2 overloads)stat('/Users/joe/test.txt');
    const stats: Statsstats.StatsBase<number>.isFile(): booleanisFile(); // true
    const stats: Statsstats.StatsBase<number>.isDirectory(): booleanisDirectory(); // false
    const stats: Statsstats.StatsBase<number>.isSymbolicLink(): booleanisSymbolicLink(); // false
    var console: Consoleconsole.Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)log(const stats: Statsstats.StatsBase<number>.size: numbersize); // 1024000 //= 1MB
  } catch (function (local var) err: unknownerr) {
    var console: Consoleconsole.Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)log(function (local var) err: unknownerr);
  }
}
function example(): Promise<void>example();

You can read more about the fs module in the official documentation.

请勿阻塞事件循环 Node.js 中的文件路径