battery level audio output on Mac

verbose-charging.js

#!/usr/bin/env node

// https://nodejs.org/api/child_process.html
const child_process = require('child_process');
child_process.spawn('/usr/bin/pmset', ['-g', 'pslog'])
  .stdout.on('data', function(chunk) {
    // parse battery info from pmset output stream
    var verbose_output = [/(\d+%)/, /(\d+:\d+)\ remaining/]
      .filter(function(expression) {
        // output contains battery info
        return expression.test(chunk);
      }).map(function(expression) {
        // parse battery info
        return expression.exec(chunk).shift().trim();
      }).join(' - ');
    // chunk is linebreak or similar
    if (!verbose_output) return;
    // log timestamp to console
    var time_stamp = new Date().toJSON().replace(/[TZ]/g, ' ');
    console.log(`${time_stamp}${verbose_output}`);
    // audio output of bettery information
    var audio_output = verbose_output
      .split(/\ +/g).concat(['-v', 'Samantha']);
    child_process.spawn('/usr/bin/say', audio_output);
  });