Read File

Read the entire contents of a file.

Usage

var readFile = require( '@stdlib/fs/read-file' );

readFile( file[, options], clbk )

Asynchronously reads the entire contents of a file.

readFile( __filename, onFile );

function onFile( error, data ) {
    if ( error ) {
        throw error;
    }
    console.log( data );
}

The function accepts the same options and has the same defaults as fs.readFile().

readFile.sync( file[, options] )

Synchronously reads the entire contents of a file.

var out = readFile.sync( __filename );
if ( out instanceof Error ) {
    throw out;
}
console.log( out );

The function accepts the same options and has the same defaults as fs.readFileSync().

Notes

The difference between this API and fs.readFileSync() is that fs.readFileSync() will throw if an error is encountered (e.g., if given a non-existent path) and this API will return an error. Hence, the following anti-pattern

```javascript
var fs = require( 'fs' );

var file = '/path/to/file.js';

// Check for existence to prevent an error being thrown...
if ( fs.existsSync( file ) ) {
    file = fs.readFileSync( file );
}
```

can be replaced by an approach which addresses existence via `error` handling.

```javascript
var readFile = require( '@stdlib/fs/read-file' );

var file = '/path/to/file.js';

// Explicitly handle the error...
file = readFile.sync( file );
if ( file instanceof Error ) {
    // You choose what to do...
    console.error( file.message );
}
```

Examples

var readFile = require( '@stdlib/fs/read-file' );

/* Sync */

var file = readFile.sync( __filename, 'utf8' );
// returns <string>

console.log( file instanceof Error );
// => false

file = readFile.sync( 'beepboop', {
    'encoding': 'utf8'
});
// returns <Error>

console.log( file instanceof Error );
// => true

/* Async */

readFile( __filename, onFile );
readFile( 'beepboop', onFile );

function onFile( error, data ) {
    if ( error ) {
        if ( error.code === 'ENOENT' ) {
            console.error( 'File does not exist.' );
        } else {
            throw error;
        }
    } else {
        console.log( data );
    }
}

CLI

Usage

Usage: read-file [options] <filepath>

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
  --enc, --encoding encoding   Encoding.
         --flag flag           Flag. Default: 'r'.

Notes

Relative file paths are resolved relative to the current working directory.
Errors are written to stderr.
File contents are written to stdout.

Examples

$ read-file ./README.md
<file_contents>