@naturalcycles/nodejs-lib/dist/stream/ndjson/transformToNDJson.js

Standard library for Node.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.transformToNDJson = void 0;
const stream_1 = require("stream");
const js_lib_1 = require("@naturalcycles/js-lib");
/**
 * Transforms objects (objectMode=true) into chunks \n-terminated JSON strings (readableObjectMode=false).
 */
function transformToNDJson(opt = {}) {
    const { strict = true, separator = '\n', sortObjects = false, useFlatstr = false } = opt;
    return new stream_1.Transform({
        writableObjectMode: true,
        readableObjectMode: false,
        transform(chunk, _, cb) {
            try {
                if (sortObjects) {
                    chunk = (0, js_lib_1._sortObjectDeep)(chunk);
                }
                if (useFlatstr) {
                    cb(null, flatstr(JSON.stringify(chunk) + separator));
                }
                else {
                    cb(null, JSON.stringify(chunk) + separator);
                }
            }
            catch (err) {
                console.error(err);
                if (strict) {
                    cb(err); // emit error
                }
                else {
                    cb(); // emit no error, but no result neither
                }
            }
        },
    });
}
exports.transformToNDJson = transformToNDJson;
/**
 * Based on: https://github.com/davidmarkclements/flatstr/blob/master/index.js
 */
function flatstr(s) {
    // eslint-disable-next-line
    s | 0;
    return s;
}