​

const selectEl1 = document.querySelector('.mySelect1')

const selectEl2 = document.querySelector('.mySelect2')

​

const config = {

  visibleOptions: 10,

  filter: true,

}

​

// add 1000 options to select2, but only 20 to select1

for(let i = 0; i < 1000; i++) {

  const newOption = document.createElement('option')

  newOption.innerText= `option ${i}`

  selectEl2.appendChild(newOption)

  if(i < 20) {

    const clone = newOption.cloneNode(true)

    selectEl1.appendChild(clone)

  }

}

​

new mdb.Select(selectEl1)

new mdb.Select(selectEl2, config)