toCsv.js

const deduceHeaders = require('../utils/deduceHeaders');
const breathe = require('../utils/breathe');

//Returns the data as a string
async function createCSV(data) {
  let files = {};
  for (const key in data) {
    let device = key;
    if (data[key]['device name'] != null) device = data[key]['device name'];
    if (data[key].streams) {
      for (const stream in data[key].streams) {
        await breathe();
        //We try to save all valid streams
        if (
          data[key].streams[stream].samples &&
          data[key].streams[stream].samples.length
        ) {
          //Prepare string
          let rows = [];
          //Get name and units to prepare headers
          let name = stream;
          if (data[key].streams[stream].name != null)
            name = data[key].streams[stream].name;
          let units;
          if (data[key].streams[stream].units != null)
            units = data[key].streams[stream].units;
          const headers = deduceHeaders({ name, units });
          let sticky = {};
          //Loop all the samples

          for (let i = 0; i < data[key].streams[stream].samples.length; i++) {
            const s = data[key].streams[stream].samples[i];
            //Check that at least we have the valid values
            if (s.value != null) {
              //Force convert to array
              if (!Array.isArray(s.value)) s.value = [s.value];
              //Update and remember sticky data
              if (s.sticky) sticky = { ...sticky, ...s.sticky };
              //If first row
              if (!rows.length) {
                let firstRow = [];
                //Add time
                if (s.cts != null) firstRow.push('cts');
                if (s.date != null) firstRow.push('date');
                //Fill missing headers
                for (let ii = 0; ii < s.value.length; ii++) {
                  firstRow.push(headers[ii] || ii);
                }
                //Add stickies headers
                firstRow.push(...Object.keys(sticky));
                //Escape commas and add first row
                rows.push(
                  firstRow.map(e => e.toString().replace(/,/g, '|')).join(',')
                );
              }

              let row = [];
              //Add time
              if (s.cts != null) row.push(s.cts);
              if (s.date != null) {
                let processedDate = s.date;
                if (typeof s.date != 'object') processedDate = new Date(s.date);
                try {
                  row.push(processedDate.toISOString());
                } catch (e) {
                  row.push(processedDate);
                }
                s.date = processedDate;
              }
              //Add all values
              s.value.forEach(v => {
                if (typeof v === 'number' || typeof v === 'string') row.push(v);
                else row.push(JSON.stringify(v));
              });
              //Add stickies values
              for (const key in sticky) row.push(sticky[key]);
              //Add line to rows
              rows.push(
                row.map(e => e.toString().replace(/,/g, '|')).join(',')
              );
            }
          }
          //Join all lines
          files[`${device}-${stream}`] = rows.join('\n');
        }
      }
    }
  }
  return files;
}

//Converts the processed data to csv
module.exports = createCSV;