buffer-readable/lib/index.js

convert a string/Buffer/Uint8Array to a readable stream, support highWaterMark and adjustable push delay

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.BufferReadable = void 0;
const stream_1 = require("stream");
class BufferReadable extends stream_1.Readable {
    constructor(buffer, opts) {
        super(Object.assign(Object.assign({}, opts), { objectMode: false }));
        this.__delay = 0;
        this.__pos = 0;
        if (Buffer.isBuffer(buffer)) {
            this.__buffer = buffer;
        }
        else if (typeof buffer === "string" || buffer instanceof Uint8Array) {
            this.__buffer = Buffer.from(buffer);
        }
        else {
            throw new Error("arguments type error");
        }
        this.__buffer_len = this.__buffer.length;
        const delay = opts === null || opts === void 0 ? void 0 : opts.delay;
        if (typeof delay === "number" && Number.isSafeInteger(delay) && delay > 0) {
            this.__delay = delay;
        }
    }
    _read(size) {
        if (this.__pos >= this.__buffer_len) {
            this.push(null);
        }
        else {
            const start = this.__pos;
            const end = start + size;
            const chunk = this.__buffer.slice(start, end);
            this.__pos = end;
            setTimeout(() => {
                this.push(chunk);
                if (end >= this.__buffer_len) {
                    this.push(null);
                }
            }, this.__delay);
        }
    }
    _destroy(error, callback) {
        this.__buffer = null;
        callback(error);
    }
}
exports.BufferReadable = BufferReadable;