Why does Node js fs readFile return a buffer instead of string

Question

I m trying to read the content of test txt which is on the same folder of the Javascript source  and display it using this code   var fs   require  fs     fs readFile  test txt   function  err  data        if  err  throw err      console log data         The content of the test txt was created on nano      Testing Node js readFile     And I m getting this   Nathan-Camposs-MacBook-Pro node test Nathan  node main js  lt Buffer 54 65 73 74 69 6e 67 20 4e 6f 64 65 2e 6a 73 20 72 65 61 64 46 69 6c 65 28 29 gt  Nathan-Camposs-MacBook-Pro node test Nathan

User · Answer

Async   fs readFile  test txt    utf8   callback     Sync   var content   fs readFileSync  test txt    utf8

User · Answer

It is returning a Buffer object   If you want it in a string  you can convert it with data toString     var fs   require  fs     fs readFile  test txt   function  err  data        if  err  throw err      console log data toString

User · Answer

The data variable contains a Buffer object  Convert it into ASCII encoding using the following syntax   data toString  ascii   0  data length    Asynchronously   fs readFile  test txt    utf8   function  error  data        if  error  throw error      console log data toString

User · Answer

Try      fs readFile  quot test txt quot    quot utf8 quot   function err  data           Basically  you need to specify the encoding

User · Answer

This comes up high on Google  so I d like to add some contextual information about the original question  emphasis mine       Why does Node js  fs readFile   return a buffer instead of string    Because files aren t always text  Even if you as the programmer know it  Node has no idea what s in the file you re trying to read  It could be a text file  but it could just as well be a ZIP archive or a JPG image     Node doesn t know   Because reading text files is tricky  Even if Node knew it were to read a text file  it still would have no idea which character encoding is used  i e  how the bytes in the file map to human-readable characters   because the character encoding itself is not stored in the file   There are ways to guess the character encoding of text files with more or less confidence  that s what text editors do when opening a file   but you usually don t want your code to rely on guesses without your explicit instruction   Buffers to the rescue   So  because it does not and can not know all these details  Node just reads the file byte for byte  without assuming anything about its contents   And that s what the returned buffer is  an unopinionated container for raw binary content  How this content should be interpreted is up to you as the developer

User · Answer

From the docs      If no encoding is specified  then the raw buffer is returned    Which might explain the  lt Buffer     gt   Specify a valid encoding  for example utf-8  as your second parameter after the filename  Such as   fs readFile  test txt    utf8   function err  data

[javascript] Why does Node.js' fs.readFile() return a buffer instead of string?

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