web-csv-toolbox - v0.15.0
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    Class StringCSVParserStream<Header, Format>

    A transform stream that converts a stream of strings into a stream of CSV records. Wraps a StringCSVParser instance to provide streaming CSV parsing.

    StringCSVParser instance to use for parsing (required). Use createStringCSVParser to create one.

    Stream-specific options (backpressureCheckInterval, etc.)

    Strategy for the writable side (default: { highWaterMark: 65536, size: chunk => chunk.length })

    Strategy for the readable side (default: { highWaterMark: 256 })

    Recommended: Use the factory function

    For simpler usage, use createStringCSVParserStream which handles parser creation internally:

    import { createStringCSVParserStream } from 'web-csv-toolbox';

    await fetch('data.csv')
      .then(res => res.body)
      .pipeThrough(new TextDecoderStream())
      .pipeThrough(createStringCSVParserStream({ header: ['name', 'age'] }))
      .pipeTo(yourProcessor);

    Direct instantiation (advanced)

    If you need direct access to the parser or want to reuse it, use the constructor directly:

    import { createStringCSVParser, StringCSVParserStream } from 'web-csv-toolbox';
    const parser = createStringCSVParser({ header: ['name', 'age'] });
    stringStream.pipeThrough(new StringCSVParserStream(parser));

    Queuing Strategy:

    • Writable side: Counts by string length (characters). Default highWaterMark is 65536 characters (≈64KB).
    • Readable side: Counts each record as 1. Default highWaterMark is 256 records.

    Backpressure Handling: The transformer monitors controller.desiredSize and yields to the event loop when backpressure is detected (desiredSize ≤ 0). This prevents blocking the main thread during heavy processing and allows the downstream consumer to catch up.

    import { createStringCSVParserStream } from 'web-csv-toolbox';

    await fetch('data.csv')
      .then(res => res.body)
      .pipeThrough(new TextDecoderStream())
      .pipeThrough(createStringCSVParserStream())
      .pipeTo(new WritableStream({
        write(record) {
          console.log(record); // { name: 'Alice', age: '30' }
        }
      }));

    import { createStringCSVParser, StringCSVParserStream } from 'web-csv-toolbox';

    const parser = createStringCSVParser({ header: ['name', 'age'] });
    const stream = new StringCSVParserStream(parser);

    stringStream.pipeThrough(stream);

    import { createStringCSVParser, StringCSVParserStream } from 'web-csv-toolbox';

    const parser = createStringCSVParser({ header: ['name', 'age'] });
    const stream = new StringCSVParserStream(
      parser,
      { backpressureCheckInterval: 50 },
      { highWaterMark: 131072, size: (chunk) => chunk.length },
      new CountQueuingStrategy({ highWaterMark: 512 })
    );

    await fetch('large-file.csv')
      .then(res => res.body)
      .pipeThrough(new TextDecoderStream())
      .pipeThrough(stream)
      .pipeTo(yourProcessor);

    Type Parameters

    • Header extends ReadonlyArray<string> = readonly string[]

      The type of the header row

    • Format extends "object" | "array" = "object"

      Output format: 'object' or 'array'

    Hierarchy

    Index

    Constructors

    constructor

    Properties

    parser readable writable

    Methods

    yieldToEventLoop

    Constructors

    Properties

    parser: {
        parse(
            chunk?: string,
            options?: { stream?: boolean },
        ): IterableIterator<CSVRecord<Header, Format>>;
    }
    readable: ReadableStream<CSVRecord<Header, Format, "keep">>

    The readable read-only property of the TransformStream interface returns the ReadableStream instance controlled by this TransformStream.

    MDN Reference

    writable: WritableStream<string>

    The writable read-only property of the TransformStream interface returns the WritableStream instance controlled by this TransformStream.

    MDN Reference

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