index.js•2.19 kB
import { Transform } from "node:stream";
import iconv from "iconv-lite";
import { Sniffer, getEncoding } from "./sniffer.js";
/**
* Sniff the encoding of a buffer, then decode it.
*
* @param buffer Buffer to be decoded
* @param options Options for the sniffer
* @returns The decoded buffer
*/
export function decodeBuffer(buffer, options = {}) {
return iconv.decode(buffer, getEncoding(buffer, options));
}
/**
* Decodes a stream of buffers into a stream of strings.
*
* Reads the first 1024 bytes and passes them to the sniffer. Once an encoding
* has been determined, it passes all data to iconv-lite's stream and outputs
* the results.
*/
export class DecodeStream extends Transform {
constructor(options) {
var _a;
super({ decodeStrings: false, encoding: "utf-8" });
this.buffers = [];
/** The iconv decode stream. If it is set, we have read more than `options.maxBytes` bytes. */
this.iconv = null;
this.readBytes = 0;
this.sniffer = new Sniffer(options);
this.maxBytes = (_a = options === null || options === void 0 ? void 0 : options.maxBytes) !== null && _a !== void 0 ? _a : 1024;
}
_transform(chunk, _encoding, callback) {
if (this.readBytes < this.maxBytes) {
this.sniffer.write(chunk);
this.readBytes += chunk.length;
if (this.readBytes < this.maxBytes) {
this.buffers.push(chunk);
callback();
return;
}
}
this.getIconvStream().write(chunk, callback);
}
getIconvStream() {
if (this.iconv) {
return this.iconv;
}
const stream = iconv.decodeStream(this.sniffer.encoding);
stream.on("data", (chunk) => this.push(chunk, "utf-8"));
stream.on("end", () => this.push(null));
this.iconv = stream;
for (const buffer of this.buffers) {
stream.write(buffer);
}
this.buffers.length = 0;
return stream;
}
_flush(callback) {
this.getIconvStream().end(callback);
}
}
export { getEncoding } from "./sniffer.js";
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