@loaders.gl/loader-utils/dist/lib/iterators/text-iterators.js

Framework-independent loaders for 3D graphics formats

// TextDecoder iterators
// TextDecoder will keep any partial undecoded bytes between calls to `decode`
export async function* makeTextDecoderIterator(arrayBufferIterator, options = {}) {
    const textDecoder = new TextDecoder(undefined, options);
    for await (const arrayBuffer of arrayBufferIterator) {
        yield typeof arrayBuffer === 'string'
            ? arrayBuffer
            : textDecoder.decode(arrayBuffer, { stream: true });
    }
}
// TextEncoder iterator
// TODO - this is not useful unless min chunk size is given
// TextEncoder will keep any partial undecoded bytes between calls to `encode`
// If iterator does not yield strings, assume arrayBuffer and return unencoded
export async function* makeTextEncoderIterator(textIterator) {
    const textEncoder = new TextEncoder();
    for await (const text of textIterator) {
        yield typeof text === 'string' ? textEncoder.encode(text) : text;
    }
}
/**
 * @param textIterator async iterable yielding strings
 * @returns an async iterable over lines
 * See http://2ality.com/2018/04/async-iter-nodejs.html
 */
export async function* makeLineIterator(textIterator) {
    let previous = '';
    for await (const textChunk of textIterator) {
        previous += textChunk;
        let eolIndex;
        while ((eolIndex = previous.indexOf('\n')) >= 0) {
            // line includes the EOL
            const line = previous.slice(0, eolIndex + 1);
            previous = previous.slice(eolIndex + 1);
            yield line;
        }
    }
    if (previous.length > 0) {
        yield previous;
    }
}
/**
 * @param lineIterator async iterable yielding lines
 * @returns async iterable yielding numbered lines
 *
 * See http://2ality.com/2018/04/async-iter-nodejs.html
 */
export async function* makeNumberedLineIterator(lineIterator) {
    let counter = 1;
    for await (const line of lineIterator) {
        yield { counter, line };
        counter++;
    }
}