This project provides CSV parsing and has been tested and used on large input files.
- Follow the Node.js streaming API
- Async and event based
- Support delimiters, quotes and escape characters
- Line breaks discovery: detected in source and reported to destination
- Data transformation
- Support for large datasets
- Complete test coverage as sample and inspiration
- no external dependencies
Important: this documentation covers the current version (0.2.x) of
node-csv-parser. The documentation for the previous version (0.1.0) is
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The following example illustrates 4 usages of the library: 1. Plug a readable stream by defining a file path 2. Direct output to a file path 3. Transform each row (optional) 4. Listen to events (optional)
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Here’s a quick example:
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Via git (or downloaded tarball):
Emitted by the stringifier when a new row is parsed and transformed. The data is the value returned by the user
transformcallback if any. Note however that the event won’t be called if transform return
nullsince the record is skipped. The callback provides two arguments.
rowis the CSV line being processed (an array or an object) and
indexis the index number of the line starting at zero
Emitted by the stringifier on each line once the data has been transformed and stringified.
Emitted when the CSV content has been parsed.
Emitted when the underlying resource has been closed. For example, when writting to a file with
csv().to.path(), the event will be called once the writing process is complete and the file closed.
Thrown whenever an error occured.
The code is organized mainly around 5 main components. The “from” properties provide convenient functions to write CSV text or to plug a Stream Reader. The “parser” takes this CSV content and transform it into an array or an object for each line. The “transformer” provides the ability to work on each line in a synchronous or asynchronous mode. The “stringifier” takes an array or an object and serializes it into CSV text. Finally, the “to” properties provide convenient functions to retrieve the text or to write to plug a Stream Writer.
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Note, even though the “parser”, “transformer” and “singifier” are available as properties, you won’t have to interact with those.
Implementation of the Readable Stream API, requesting that no further data be sent until resume() is called.
Implementation of the Readable Stream API, resuming the incoming ‘data’ events after a pause().
Implementation of the Writable Stream API with a larger signature. Data may be a string, a buffer, an array or an object.
If data is a string or a buffer, it could span multiple lines. If data is an object or an array, it must represent a single line. Preserve is for line which are not considered as CSV data.
Terminate the parsing. Call this method when no more csv data is
to be parsed. It implement the StreamWriter API by setting the
property to “false” and emitting the
Register the transformer callback. The callback is a user provided function call on each line to filter, enrich or modify the dataset. More information in the “transforming data” section.
Unified mechanism to handle error, emit the error and mark the stream as non readable and non writable.