判断列表为空

zhangjian

2023-08-07 6b009b0f6d3ef3aee97c362cebcd679d1b9088a3

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'use strict';
const bufferStream = require('./buffer-stream');
 
function getStream(inputStream, opts) {
    if (!inputStream) {
        return Promise.reject(new Error('Expected a stream'));
    }
 
    opts = Object.assign({maxBuffer: Infinity}, opts);
 
    const maxBuffer = opts.maxBuffer;
    let stream;
    let clean;
 
    const p = new Promise((resolve, reject) => {
        const error = err => {
            if (err) { // null check
                err.bufferedData = stream.getBufferedValue();
            }
 
            reject(err);
        };
 
        stream = bufferStream(opts);
        inputStream.once('error', error);
        inputStream.pipe(stream);
 
        stream.on('data', () => {
            if (stream.getBufferedLength() > maxBuffer) {
                reject(new Error('maxBuffer exceeded'));
            }
        });
        stream.once('error', error);
        stream.on('end', resolve);
 
        clean = () => {
            // some streams doesn't implement the `stream.Readable` interface correctly
            if (inputStream.unpipe) {
                inputStream.unpipe(stream);
            }
        };
    });
 
    p.then(clean, clean);
 
    return p.then(() => stream.getBufferedValue());
}
 
module.exports = getStream;
module.exports.buffer = (stream, opts) => getStream(stream, Object.assign({}, opts, {encoding: 'buffer'}));
module.exports.array = (stream, opts) => getStream(stream, Object.assign({}, opts, {array: true}));