path module

_u dirname: Get the absolute path directory of the current file

_u filename: Get the path to the current file

ctx.body = {
        dirName: __dirname, 
        fileName: __filename 
}
//{"dirName":"D:\\WEB\\koa_proj","fileName":"D:\\WEB\\koa_proj\\app.js"}

path.join(p1, p2): for splicing paths

//"D:\\WEB\\koa_proj\\file.txt"
path.join(__dirname, '/file.txt');

path.basename(path, ext): Used to get the file name in the path including the suffix name

/**
ext A file suffix name, such as.txt, with this parameter takes the file name, excluding the suffix
**/
let filePath = path.join(__dirname, '/file.txt')
path.basename(filePath)//"file.txt"
path.basename(filePath, '.txt')//"file"

path.dirname(path): The name of the directory used to get a full file path, similar to u dirname

let filePath = path.join(__dirname, '/file.txt');
//"D:\\WEB\\koa_proj"
path.dirname(filePath)

path.delimiter: delimiter, in windows';', in linux':'

path.extname(p): the name or name used to get the file

path.extname(filePath)//".txt"

path.parse(p): The path used to parse a file and generate an object that includes the directory, file name, and file suffix

path.parse(filePath)
/*
{
    "root":"D:\\",
    "dir":"D:\\WEB\\koa_proj",
    "base":"file.txt",
    "ext":".txt",
    "name":"file"
}
*/

path.format: Used to convert an object to its path, as opposed to the path.parse process

path.isAbsolute(p): Used to determine whether a file change is a relative or absolute path

path.normalize(p): Output file paths\, depending on the operating system, will be processed uniformly with inconsistent delimiters in the paths

path.normalize('D:/WEB\\koa_proj') //"normalizePath":"D:\\WEB\\koa_proj"

path.relative(from, to): Used to get the relative path from the from path to the to path

path.resolve(p1, p2): For path splicing, the absolute path relative to the application is always obtained, path.resolve:** follows the path with/so the last/file is used as the base for string splicing

path.resolve(__dirname, './public','./file.txt')
//"D:\\WEB\\koa_proj\\public\\file.txt"

path.sep: Gets the file path action symbol for the current system, which is'//'in window

app.use(route.get('/index', async ctx => {
    console.log(__dirname);
    console.log(__filename);
    ctx.body = {
        dirName: __dirname,
        fileName: __filename ,
        filePath: path.join(__dirname, './file.txt'),
        extFileName: path.basename(filePath, '.txt'),
        dirPathName: path.dirname(filePath),
        pathObj: path.parse(filePath),
        normalizePath: path.normalize('D:/WEB\\koa_proj'),
        relativePath: path.relative(path.join(__dirname, 'file.txt'), path.join(__dirname, '/js/file.js')),
        jsPath: path.join(__dirname, relativePath),
        resolvePath: path.resolve(__dirname, './public','./file.txt'),
        resolvePath2: path.resolve(__dirname, '/js/index.js', '/css/index.css'),
        sep: path.sep
    }
}));

fs module

fs.statSync(p, callback): Used to detect the existence of a file and error occurs when the file does not exist: no such file or directory, stat'D:WEBkoa_projfile.txt'

fs.statSync(__filename);
{"dev":2585188530,"mode":33206,"nlink":1,"uid":0,"gid":0,"rdev":0,"ino":844424930559515,"size":777,"atimeMs":1526185196399,"mtimeMs":1526185196399,"ctimeMs":1526185196399,"birthtimeMs":1524389744769,"atime":"2018-05-13T04:19:56.399Z","mtime":"2018-05-13T04:19:56.399Z","ctime":"2018-05-13T04:19:56.399Z","birthtime":"2018-04-22T09:35:44.769Z"}

fs.writeFileSync(p, data): Used to write data to a file and create a corresponding file if it does not exist

fs.writeFileSync(path.join(__dirname, './index.js'), 'hello word')

fs.appendFileSync(p, data[,option]): Used to append content to a file and create it if it does not exist

fs.appendFileSync(path.join(__dirname, './index.js'), 'hi');

fs.unlink(p): Used to delete a file and error if the file does not exist or the deletion fails

fs.unlinkSync(path.join(__dirname, './index.js'));

fs.readFileSync(p[,option]): Used to read file contents

/*
*Data read when no encoding format is specified is Buffer
*/
fs.readFileSync(path.join(__dirname, './index.js'), 'utf-8');

fs.renameSync(oldPath, newPath): Used to move or rename files, the directory must exist when moving the directory

fs.renameSync(path.join(__dirname, './index.js'), path.join(__dirname, './index2.js'));

fs.mkdir(p, name): Used to create a directory, the directory created must not exist, otherwise an error will be reported

fs.mkdirSync(path.join(__dirname, 'test'));

fs.rmdirSync(p): Used to delete a file directory

 fs.rmdirSync(path.join(__dirname, './test'));

fs.readdirSysn(p): Used to read files and directories under a directory

fs.readdirSync(path.join(__dirname, './js'));