@beenotung/tslib/stream.js

utils library in Typescript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.readStreamByLine = readStreamByLine;
exports.readStreamAllLine = readStreamAllLine;
exports.readStreamAsString = readStreamAsString;
const stream_1 = require("stream");
/**
 * @description lineNum start from 0
 * */
function readStreamByLine(stream, _onLine, _onError, _onComplete) {
    const _lineStream = new stream_1.Stream();
    let _lineNum = -1;
    let acc = '';
    const onLine = (line) => {
        _lineNum++;
        const data = { line, lineNum: _lineNum };
        _lineStream.emit('data', data);
        if (_onLine) {
            _onLine(line, _lineNum);
        }
    };
    const onError = (e) => {
        _lineStream.emit('error', e);
        if (_onError) {
            _onError(e);
        }
    };
    const onComplete = () => {
        if (acc !== '') {
            console.warn('stream ends without newline');
            onLine(acc);
        }
        _lineStream.emit('end');
        if (_onComplete) {
            _onComplete();
        }
    };
    stream.on('data', s => {
        acc += s;
        const ss = acc.split('\n');
        if (ss.length === 1) {
            return;
        }
        const n = ss.length - 1;
        for (let i = 0; i < n; i++) {
            onLine(ss[i]);
        }
        acc = ss[n];
    });
    stream.on('error', onError);
    stream.on('end', onComplete);
    return _lineStream;
}
function readStreamAllLine(stream) {
    return new Promise((resolve, reject) => {
        const lines = [];
        readStreamByLine(stream, line => lines.push(line), e => reject(e), () => resolve(lines));
    });
}
function readStreamAsString(stream, lineFeed = '\n') {
    return readStreamAllLine(stream).then(lines => lines.join(lineFeed));
}