Papa Parse

In Node.js environments, Papa Parse can parse Readable Streams in addition to strings.

Important Constraints:

• If using a stream, the encoding option must be a Node-supported character encoding.
• The following options are unavailable when parsing a stream: Papa.LocalChunkSize, Papa.RemoteChunkSize, download, withCredentials, and worker.

Node.js Streaming Style (.pipe): To use Node's .pipe() method, pipe your Readable Stream to the stream returned by Papa.parse(Papa.NODE_STREAM_INPUT, options).

When using this streaming mode:

• The following options are unavailable: Papa.LocalChunkSize, Papa.RemoteChunkSize, download, withCredentials, worker, step, and complete.
• Use the 'data' event to process chunks: stream.on('data', callback).
• Use the 'end' event to signal the end of the stream: stream.on('end', callback).

The config object passed to Papa.unparse() controls how JSON is converted to CSV. Common options include:

When creating a new Parser instance, you can provide a configuration object to control the parsing behavior.

Key configuration options include:

• delimiter: The character used to separate fields (defaults to ,).
• newline: The character used for line breaks (\n, \r, or \r\n).
• comments: A character that indicates a comment line (e.g., #). If set to true, it defaults to #.
• quoteChar: The character used to wrap fields containing special characters (defaults to ").
• escapeChar: The character used to escape the quoteChar.
• step: A callback function executed for every row parsed. This is useful for processing large files row-by-row to save memory.
• preview: The number of rows to parse before stopping.
• fastMode: A boolean to enable a faster, simplified parsing logic (skips some complex quote handling).
• header: If true, the first row is treated as headers. If duplicate headers are found, they are automatically renamed with a suffix (e.g., header_1).
• transformHeader: A function called for each header to transform its value.

var parser = new Parser({
    delimiter: ",",
    newline: "\n",
    comments: "#",
    header: true,
    step: function(results) {
        console.log("Row parsed:", results.data);
    }
});

The config object passed to Papa.parse() controls how the CSV is processed. Common options include:

Use Papa.parse() to convert CSV data into JSON. The function accepts a string, a File object, or a URL. It supports various input types including local files, remote files (via streaming), and Node.js streams.

Key features:

• Automatic Delimiter Detection: If no delimiter is provided, Papa Parse attempts to guess it.
• Dynamic Typing: Automatically converts values to numbers, booleans, or dates.
• Workers: Can run in a Web Worker to prevent UI blocking.
• Streaming: Supports chunked parsing for large files via step or chunk callbacks.

// Parsing a string
Papa.parse("name,age\nJohn,30\nJane,25", {
    header: true,
    complete: function(results) {
        console.log(results.data);
    }
});

// Parsing a file (e.g., from an <input type="file">)
const file = document.getElementById('file-input').files[0];
Papa.parse(file, {
    header: true,
    complete: function(results) {
        console.log(results.data);
    }
});