aead-stream/dist/chunkify.js

Authenticated encryption on arbitrary large files

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.chunkify = void 0;
/**
 * Stream transformation function that outputs chucks of a defined size.
 * The last chunk contains the rest of the data and may be smaller than the other chunks
 *
 * @param size the size of the chucks (except the last one)
 * @param stream the input stream of data
 */
async function* chunkify(size, stream) {
    if (typeof stream[Symbol.asyncIterator] !== "function") {
        throw new TypeError("invalid input - expected an async iterable");
    }
    const buffer = new Uint8Array(size);
    let length = 0;
    for await (const chunk of stream) {
        let offset = 0;
        do {
            const slice = chunk.slice(offset, offset + Math.min(size - length, chunk.length));
            buffer.set(slice, length);
            length += slice.length;
            offset += slice.length;
            if (length === size) {
                yield buffer;
                length = 0;
            }
        } while (offset < chunk.length);
    }
    if (length > 0) {
        yield buffer.slice(0, length);
    }
}
exports.chunkify = chunkify;