tasmota-esp-web-tools/dist/util/line-break-transformer.js

Web tools for ESP devices

export class LineBreakTransformer {
    constructor() {
        this.chunks = "";
    }
    transform(chunk, controller) {
        // Append new chunks to existing chunks.
        this.chunks += chunk;
        // Split on \r\n, lone \r, or lone \n — capturing the separator so we can
        // distinguish a lone \r (overwrite intent) from a normal newline.
        const re = /\r\n|\r|\n/g;
        let lastIndex = 0;
        let match;
        while ((match = re.exec(this.chunks)) !== null) {
            // If this is a lone \r at the very end of the buffer, leave it so it can
            // be combined with a possible following \n in the next chunk.
            if (match[0] === "\r" && match.index === this.chunks.length - 1) {
                break;
            }
            const line = this.chunks.substring(lastIndex, match.index);
            // Emit with \r suffix only for lone \r (overwrite), \n for everything else.
            const suffix = match[0] === "\r" ? "\r" : "\n";
            controller.enqueue(line + suffix);
            lastIndex = re.lastIndex;
        }
        this.chunks = this.chunks.substring(lastIndex);
    }
    flush(controller) {
        // When the stream is closed, flush any remaining chunks out.
        controller.enqueue(this.chunks);
    }
}