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csv-parse
Advanced tools
The csv-parse package is a flexible Node.js library that provides a parser converting CSV text input into arrays or objects. It implements the Node.js stream.Transform API. It is also capable of converting large datasets and supports many advanced features such as streaming and asynchronous processing.
Parsing CSV to Arrays
This feature allows you to parse CSV data into arrays. Each row in the CSV data becomes an array.
const parse = require('csv-parse');
const assert = require('assert');
const input = 'a,b,c\nd,e,f';
parse(input, function(err, output){
assert.deepEqual(output, [['a', 'b', 'c'], ['d', 'e', 'f']]);
});
Parsing CSV with Column Mapping
This feature allows you to map CSV columns to object properties, so each row in the CSV data becomes an object with named properties.
const parse = require('csv-parse');
const assert = require('assert');
const input = 'a,b,c\nd,e,f';
const parser = parse({columns: true}, function(err, records){
assert.deepEqual(records, [{a: 'd', b: 'e', c: 'f'}]);
});
parser.write(input);
parser.end();
Asynchronous Iteration
This feature allows for asynchronous iteration over the parsed records, which is useful for handling large CSV files or streams.
const parse = require('csv-parse');
const fs = require('fs');
const parser = fs.createReadStream('/path/to/csv-file.csv').pipe(parse({columns: true}));
(async () => {
for await (const record of parser) {
// Work with each record
}
})();
Papa Parse is a powerful CSV parser that can handle large files and malformed input gracefully. It works in both browser and server environments. Compared to csv-parse, Papa Parse has a more user-friendly API and can automatically detect delimiters.
Fast-csv is another CSV parsing and formatting library for Node.js. It provides a simple API and supports both stream and callback-based processing. It is known for its speed and efficiency, but csv-parse offers more advanced features and customization options.
csvtojson is a full-featured CSV parser library that converts CSV to JSON. One of its main differences from csv-parse is that it focuses on the JSON output format, whereas csv-parse provides more flexibility in handling the parsed data.
This project is part of the CSV module
and is a parser converting input CSV text into arrays or objects and
implementing the Node.js stream.Transform
API. It is also providing a simple
callback-base API for converniency. It is both extremely easy to use and
powerfull. It was released since 2010 and is tested against very large dataset
by a large community.
The full documentation of the CSV parser is available here.
This module is to be considered in alpha stage. It is part of an ongoing effort to split the current CSV module into complementary modules with a cleaner design and the latest stream implementation. However, the code has been imported with very little changes and you should feel confident to use it in your code.
Run npm install csv
to install the full csv module or run
npm install csv-parse
if you are only interested by the CSV parser.
Use the callback style API for simplicity or the stream based API for scalability.
The parser receive a string and return an array inside a user-provided
callback. This example is available with the command node samples/callback.js
.
var parse = require('csv-parse');
input = '#Welcome\n"1","2","3","4"\n"a","b","c","d"';
parse(input, {comment: '#'}, function(err, output){
output.should.eql([ [ '1', '2', '3', '4' ], [ 'a', 'b', 'c', 'd' ] ]);
});
// node samples/stream.js
var parse = require('csv-parse');
output = [];
parser = parse({delimiter: ':'})
parser.on('readable', function(){
while(row = parser.read()){
output.push(row)
}
});
parser.on('error', function(err){
consol.log(err.message);
});
parser.on('finish', function(){
output.should.eql([
[ 'root','x','0','0','root','/root','/bin/bash' ],
[ 'someone','x','1022','1022','a funny cat','/home/someone','/bin/bash' ]
]);
});
parser.write("root:x:0:0:root:/root:/bin/bash\n");
parser.write("someone:x:1022:1022:a funny cat:/home/someone:/bin/bash\n");
parser.end()
One usefull function part of the Stream API is pipe
to interact between
multiple streams. You may use this function to pipe a stream.Readable
string
source to a stream.Writable
object destination. The next example available as
node samples/pipe.js
read the file, parse its content and transform it.
output = [];
parser = parse({delimiter: ':'})
input = fs.createReadStream('/etc/passwd');
transformer = transform(function(row, callback){
setTimeout(function(){
callback(null, row.join(' ')+'\n');
}, 500);
}, {parallel: 10});
input.pipe(parser).pipe(transformer).pipe(process.stdout);
Most of the generator is imported from its parent project CSV in a effort to split it between the generator, the parser, the transformer and the stringifier.
Tests are executed with mocha. To install it, simple run npm install
followed by npm test
. It will install mocha and its dependencies in your
project "node_modules" directory and run the test suite. The tests run
against the CoffeeScript source files.
To generate the JavaScript files, run make build
.
The test suite is run online with Travis against the versions 0.9, 0.10 and 0.11 of Node.js.
FAQs
CSV parsing implementing the Node.js `stream.Transform` API
The npm package csv-parse receives a total of 4,108,596 weekly downloads. As such, csv-parse popularity was classified as popular.
We found that csv-parse demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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