js help

 // find inside array
 let res =  await this.state.categories.find(data => {
        return data.CategoryName === value
      })
// empty object
Object.keys(this.q).forEach(key => {
        this.q[key] = ''
      })
//merge two objects
Object.assign(obj1,obj2)


//delete element from object
delete obj.id

// conver time to day,hour,min sec
helper.calcDayHourMin = function secondsToString (seconds) {
  var numdays = Math.floor(seconds / 86400)
  var numhours = Math.floor((seconds % 86400) / 3600)
  var numminutes = Math.floor(((seconds % 86400) % 3600) / 60)
  var numseconds = ((seconds % 86400) % 3600) % 60
  return numdays + 'days' + numhours + 'hr' + numminutes + 'mins'
}
// file extension
let fileName = file.name
  var nameLen = fileName.length
  var lastDotPos = fileName.lastIndexOf('.')
  var fileNameSub = false
  if (lastDotPos === -1) {
    fileNameSub = false
  } else {
    fileNameSub = fileName.substr(lastDotPos + 1, nameLen)
  }