What is the difference between dirname and in node js

Question

When programming in Node js and referencing files that are located somewhere in relation to your current directory  is there any reason to use the   dirname variable instead of just a regular     I ve been using    thus far in my code and just discovered the existence of   dirname  and essentially want to know whether it would be smart to convert my    s to that  and if so  why that would be a smart idea

User · Answer

refers to the current working directory  except in the require   function  When using require    it translates    to the directory of the current file called    dirname is always the directory of the current file   For example  with the following file structure   home user dir files config json       hello    world       home user dir files somefile txt  text file    home user dir dir js  var fs   require  fs     console log require    files config json     console log fs readFileSync    files somefile txt    utf8       If I cd into  home user dir and run node dir js I will get    hello   world    text file   But when I run the same script from  home user  I get    hello   world     Error  ENOENT  no such file or directory    files somefile txt      at Object openSync  fs js 228 18      at Object readFileSync  fs js 119 15      at Object  lt anonymous gt    home user dir dir js 4 16      at Module  compile  module js 432 26      at Object  js  module js 450 10      at Module load  module js 351 31      at Function  load  module js 310 12      at Array 0  module js 470 10      at EventEmitter  tickCallback  node js 192 40    Using    worked with require but not for fs readFileSync  That s because for fs readFileSync     translates into the cwd  in this case  home user    And  home user files somefile txt does not exist

User · Answer

The gist In Node js    dirname is always the directory in which the currently executing script resides  see this   So if you typed   dirname into  d1 d2 myscript js  the value would be  d1 d2  By contrast    gives you the directory from which you ran the node command in your terminal window  i e  your working directory  when you use libraries like path and fs  Technically  it starts out as your working directory but can be changed using process chdir    The exception is when you use   with require    The path inside require is always relative to the file containing the call to require  For example    Let s say your directory structure is  dir1    dir2     pathtest js  and pathtest js contains var path   require  quot path quot    console log  quot      s quot   path resolve  quot   quot     console log  quot   dirname    s quot   path resolve   dirname     and you do cd  dir1 dir2 node pathtest js  you get      dir1 dir2   dirname    dir1 dir2  Your working directory is  dir1 dir2 so that s what   resolves to  Since pathtest js is located in  dir1 dir2 that s what   dirname resolves to as well  However  if you run the script from  dir1 cd  dir1 node dir2 pathtest js  you get      dir1   dirname    dir1 dir2  In that case  your working directory was  dir1 so that s what   resolved to  but   dirname still resolves to  dir1 dir2  Using   inside require    If inside dir2 pathtest js you have a require call into include a file inside dir1 you would always do require     thefile    because the path inside require is always relative to the file in which you are calling it  It has nothing to do with your working directory

[node.js] What is the difference between __dirname and ./ in node.js?

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