ya-csv
Event based CSV parser and writer for Node.js suitable for processing large CSV streams.
// A simple echo program:
var csv = require('ya-csv');
var reader = csv.createCsvStreamReader(process.openStdin());
var writer = csv.createCsvStreamWriter(process.stdout);
reader.addListener('data', function(data) {
writer.writeRecord(data);
});
Installation
npm install ya-csv
Current version requires at least Node.js v0.2.3 and it's tested with Node.js v0.4.12, 0.6.11 and 0.7.5. Hope it works with the other versions in between too.
Features
- event based, suitable for processing big CSV streams
- configurable separator, quote and escape characters (comma, double-quote and double-quote by default)
- ignores lines starting with configurable comment character (off by default)
- supports memory-only streaming
More examples
Echo first column of the data.csv file:
// equivalent of csv.createCsvFileReader('data.csv')
var reader = csv.createCsvFileReader('data.csv', {
'separator': ',',
'quote': '"',
'escape': '"',
'comment': '',
});
var writer = new csv.CsvWriter(process.stdout);
reader.addListener('data', function(data) {
writer.writeRecord([ data[0] ]);
});
Return data in objects rather than arrays: either by grabbing the column names form the header row (first row is not passed to the data listener):
var reader = csv.createCsvFileReader('data.csv', { columnsFromHeader: true });
reader.addListener('data', function(data) {
// supposing there are so named columns in the source file
sys.puts(data.col1 + " ... " + data.col2);
});
... or by providing column names from the client code (first row is passed to the data listener in this case):
var reader = csv.createCsvFileReader('data.csv');
reader.setColumnNames([ 'col1', 'col2' ]);
reader.addListener('data', function(data) {
sys.puts(data.col1 + " ... " + data.col2);
});
Note reader.setColumnNames() resets the column names so next invocation of the data listener will again receive the data in an array rather than an object.
Convert the /etc/passwd file to comma separated format, drop commented lines and dump the results to the standard output:
var reader = csv.createCsvFileReader('/etc/passwd', {
'separator': ':',
'quote': '"',
'escape': '"',
'comment': '#',
});
var writer = new csv.CsvWriter(process.stdout);
reader.addListener('data', function(data) {
writer.writeRecord(data);
});
Parsing an upload as the data comes in, using node-formidable:
upload_form.onPart = function(part) {
if (!part.filename) { upload_form.handlePart(part); return }
var reader = csv.createCsvFileReader({'comment': '#'});
reader.addListener('data', function(data) {
saveRecord(data);
});
part.on('data', function(buffer) {
// Pipe incoming data into the reader.
reader.parse(buffer);
});
part.on('end', function() {
reader.end()
}
}
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