javascript 检查文件是否存在于 Gulp 中

Check if file exist in Gulp

提问by Caio Kawasaki

I need to check if a file exists in a gulp task, i know i can use some node functions from node, there are two:

我需要检查一个文件是否存在于 gulp 任务中，我知道我可以使用 node 的一些 node 函数，有两个：

fs.exists()and fs.existsSync()

fs.exists()和 fs.existsSync()

The problem is that in the node documentation, is saying that these functions will be deprecated

问题是在节点文档中，说这些功能将被弃用

回答by Alexander

You can use fs.access

您可以使用 fs.access

fs.access('/etc/passwd', (err) => {
    if (err) {
        // file/path is not visible to the calling process
        console.log(err.message);
        console.log(err.code);
    }
});

List of available error codes here

可用错误代码列表在这里

---

---

Using fs.access()to check for the accessibility of a file before calling fs.open(), fs.readFile()or fs.writeFile()is not recommended. Doing so introduces a race condition, since other processes may change the file's state between the two calls. Instead, user code should open/read/write the file directly and handle the error raised if the file is not accessible.

使用fs.access()之前调用来检查文件的可访问性fs.open(), fs.readFile()或fs.writeFile()不推荐。这样做会引入竞争条件，因为其他进程可能会在两次调用之间更改文件的状态。相反，用户代码应该直接打开/读取/写入文件，并在文件不可访问时处理引发的错误。

回答by Raulucco

You could add

你可以添加

var f;

try {
  var f = require('your-file');
} catch (error) {

  // ....
}

if (f) {
  console.log(f);
}

回答by Hyman Steam

As of 2018, you can use fs.existsSync():

截至 2018 年，您可以使用fs.existsSync()：

fs.exists() is deprecated, but fs.existsSync() is not. The callback parameter to fs.exists() accepts parameters that are inconsistent with other Node.js callbacks. fs.existsSync() does not use a callback.

fs.exists() 已被弃用，但 fs.existsSync() 不是。fs.exists() 的回调参数接受与其他 Node.js 回调不一致的参数。fs.existsSync() 不使用回调。

See this answer for more details.

有关更多详细信息，请参阅此答案。

回答by Ithar

I believe fs-accesspackage has been depreciated alternatively you may want to use:

我相信fs-access包已经折旧了，或者你可能想使用：

path-exists.

path-exists.

file-exists.

file-exists.

Intracutions (path-exists):

Intracutions（路径存在）：

npm install path-exists --save

const myFile = '/my_file_to_ceck.html';
const exists = pathExists.sync(myFile);
console.log(exists);

Intracutions (file-exists):

Intracutions（文件存在）：

npm install file-exists --save


const fileExists = require('file-exists');
const myFile = '/my_file_to_ceck.html';
fileExists(myFile, (err, exists) => console.log(exists))

NPM Link: path exists

NPM 链接：路径存在

NPM Link: file exists

NPM 链接：文件存在

回答by David Lemon

The node documentatión does not recommend using stat to check wether a file exists:

节点文档不建议使用 stat 检查文件是否存在：

Using fs.stat() to check for the existence of a file before calling fs.open(), fs.readFile() or fs.writeFile() is not recommended. Instead, user code should open/read/write the file directly and handle the error raisedif the file is not available.

To check if a file exists without manipulating it afterwards, fs.access() is recommended.

不推荐在调用 fs.open()、fs.readFile() 或 fs.writeFile() 之前使用 fs.stat() 检查文件是否存在。相反，用户代码应该直接打开/读取/写入文件，并在文件不可用时处理引发的错误。

要检查文件是否存在而不对其进行操作，建议使用 fs.access()。

If you don't need to read or write the file you should use fs.access, the simple and asynchronous way is:

如果您不需要读取或写入您应该使用的文件fs.access，简单且异步的方法是：

try {
 fs.accessSync(path)
 // the file exists
}catch(e){
 // the file doesn't exists
}