text: 
  let list=[
      {email:'xx'},
      {email:'by'},
      {email:'wry'},
      {email:'sss'}
  ]
  
  console.log(list.map(data=>data.email).reduce((previousValue, currentValue) => `${previousValue},${currentValue}`))
  // console.log(list.reduce((accumulator, currentValue) => `${currentValue.property}`));