_ _ _ _____ _______ __ _____ | \ | | | | / ____|/ ____\ \ / /| __ \ | \| | ___ __| | ___ | | | (___ \ \ / / | |__) |_ _ _ __ ___ ___ _ __ | . ` |/ _ \ / _` |/ _ \| | \___ \ \ \/ / | ___/ _` | '__/ __|/ _ \ '__| | |\ | (_) | (_| | __/| |____ ____) | \ / | | | (_| | | \__ \ __/ | |_| \_|\___/ \__,_|\___| \_____|_____/ \/ |_| \__,_|_| |___/\___|_|
This project provide CSV parsing and has been tested and used on large source file (over 2Gb).
- Support delimiter, quote and escape characters
- Line breaks discovery: line breaks in source are detected and reported to destination
- Data transformation
- Asynch and event based
- Support for large datasets
- Complete test coverage as sample and inspiration
Using the library is a 4 steps process:
- Create a source
- Create a destination (optional)
- Transform the data (optional)
- Listen to events (optional)
Here is a example:
// node samples/sample.js
var csv = require('csv');
csv()
.fromPath(__dirname+'/sample.in')
.toPath(__dirname+'/sample.out')
.transform(function(data){
data.unshift(data.pop());
return data;
})
.on('data',function(data,index){
console.log('#'+index+' '+JSON.stringify(data));
})
.on('end',function(count){
console.log('Number of lines: '+count);
})
.on('error',function(error){
console.log(error.message);
});
// Print sth like:
// #0 ["2000-01-01","20322051544","1979.0","8.8017226E7","ABC","45"]
// #1 ["2050-11-27","28392898392","1974.0","8.8392926E7","DEF","23"]
// Number of lines: 2
Via git (or downloaded tarball):
$ git clone http://github.com/wdavidw/node-csv-parser.git
Then, simply copy or link the ./lib/csv.js file into your $HOME/.node_libraries folder or inside a declared path folder.
Via npm:
$ npm install csv
The following method are available:
-
fromPath
Take a file path as first argument and optionally on object of options as a second arguments. -
fromStream
Take a readable stream as first argument and optionally on object of options as a second arguments. -
from
Take a string, a buffer, an array or an object as first argument and optionally some options as a second arguments.
Options are:
-
delimiter
Set the field delimiter, one character only, default to comma. -
quote
Set the field delimiter, one character only, default to double quotes. -
escape
Set the field delimiter, one character only, default to double quotes. -
columns
List of fields or true if autodiscovered in the first CSV line, impact thetransform
argument and thedata
event by providing an object instead of an array, order matters, see the transform and the columns section below. -
encoding
Default to 'utf8', apply when a readable stream is created. -
trim
If true, ignore whitespace immediately around the delimiter, default to false. -
ltrim
If true, ignore whitespace immediately following the delimiter (i.e. left-trim all fields), default to false. -
rtrim
If true, ignore whitespace immediately preceding the delimiter (i.e. right-trim all fields), default to false.
The following method are available:
-
write
Take a string, an array or an object, implementation of the StreamWriter API. -
end
Terminate the stream, implementation of the StreamWriter API. -
toPath
Take a file path as first argument and optionally on object of options as a second arguments. -
toStream
Take a readable stream as first argument and optionally on object of options as a second arguments.
Options are:
-
delimiter
Default to the delimiter read option. -
quote
Default to the quote read option. -
escape
Default to the escape read option. -
columns
List of fields, apply whentransform
return an object, order matters, see the transform and the columns sections below. -
encoding
Default to 'utf8', apply when a writable stream is created. -
header Display the column names on the first line if the columns option is provided.
-
lineBreaks
String used to delimit record rows or a special value; special values are 'auto', 'unix', 'mac', 'windows', 'unicode'; default to 'auto' (discovered in source). -
flags
Default to 'w', 'w' to create or overwrite an file, 'a' to append to a file. Apply when using thetoPath
method. -
bufferSize
Internal buffer holding data before being flush into a stream. Apply when destination is a stream. -
end
Prevent callingend
on the destination, so that destination is no longer writable, similar to passing{end: false}
option instream.pipe()
.
You may provide a callback to the transform
method. The contract is quite simple, you receive an array of fields for each record and return the transformed record. The return value may be an array, an associative array, a string or null. If null, the record will simply be skipped.
Unless you specify the columns
read option, data
are provided as arrays, otherwise they are objects with keys matching columns names.
When the returned value is an array, the fields are merge in order. When the returned value is an object, it will search for the columns
property in the write or in the read options and smartly order the values. If no columns
options are found, it will merge the values in their order of appearance. When the returned value is a string, it is directly sent to the destination source and it is your responsibility to delimit, quote, escape or define line breaks.
Example of transform returning a string
// node samples/transform.js
var csv = require('csv');
csv()
.fromPath(__dirname+'/transform.in')
.toStream(process.stdout)
.transform(function(data,index){
return (index>0 ? ',' : '') + data[0] + ":" + data[2] + ' ' + data[1];
});
// Print sth like:
// 82:Zbigniew Preisner,94:Serge Gainsbourg
By extending the Node EventEmitter
class, the library provide a few useful events:
-
data (function(data, index){}) Thrown when a new row is parsed after the
transform
callback and with the data being the value returned bytransform
. Note however that the event won't be call if transform returnnull
since the record is skipped. The callback provide two arguments:data
is the CSV line being processed (by default as an array)index
is the index number of the line starting at zero -
end In case your redirecting the output to a file using the
toPath
method, the event will be called once the writing process is complete and the file closed. -
error Thrown whenever an error is captured.
Columns names may be provided or discovered in the first line with the read options columns
. If defined as an array, the order must match the one of the input source. If set to true
, the fields are expected to be present in the first line of the input source.
You can define a different order and even different columns in the read options and in the write options. If the columns
is not defined in the write options, it will default to the one present in the read options.
When working with fields, the transform
method and the data
events receive their data
parameter as an object instead of an array where the keys are the field names.
// node samples/column.js
var csv = require('csv');
csv()
.fromPath(__dirname+'/columns.in',{
columns: true
})
.toStream(process.stdout,{
columns: ['id', 'name']
})
.transform(function(data){
data.name = data.firstname + ' ' + data.lastname
return data;
});
// Print sth like:
// 82,Zbigniew Preisner
// 94,Serge Gainsbourg
Tests are executed with expresso. To install it, simple use npm install -g expresso
.
To run the tests expresso test
- David Worms : https://github.com/wdavidw
- Will White : https://github.com/willwhite
- Justin Latimer : https://github.com/justinlatimer
- jonseymour : https://github.com/jonseymour
- pascalopitz : https://github.com/pascalopitz
- Josh Pschorr : https://github.com/jpschorr
- Pavel Kolesnikov "ya-csv": http://github.com/koles/ya-csv
- Chris Williams "node-csv": http://github.com/voodootikigod/node-csv