web-csv-toolbox - v0.14.0
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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

    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 })

    Follows the Web Streams API pattern where queuing strategies are passed as constructor arguments, similar to CSVLexerTransformer and CSVRecordAssemblerTransformer.

    Default 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 { FlexibleStringObjectCSVParser } from './models/FlexibleStringObjectCSVParser.js';
    import { StringCSVParserStream } from './stream/StringCSVParserStream.js';

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

    new ReadableStream({
      start(controller) {
        controller.enqueue("Alice,30\r\n");
        controller.enqueue("Bob,25\r\n");
        controller.close();
      }
    })
      .pipeThrough(stream)
      .pipeTo(new WritableStream({
        write(record) {
          console.log(record);
        }
      }));
    // { name: 'Alice', age: '30' }
    // { name: 'Bob', age: '25' }

    const parser = new FlexibleStringObjectCSVParser({ 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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