ITHOME

//========2 array find duplicates========

var j = ['IdA', 'ket', 'IdC', 'IdD', 'chj'];

var k = ['ket', 'chj', 'IdF', 'IdA'];

var r = j.filter(function(val) {

  return k.indexOf(val) != -1;

});

console.log(r);

var repeatD = r

log("Repeat:"+repeatD)

var repeatDataIndexj = getRepeatDataIndex(repeatD,j)

log("Repeat indexes for array j:"+repeatDataIndexj)

var repeatDataIndexk = getRepeatDataIndex(repeatD,k)

log("Repeat indexes for array k:"+repeatDataIndexk)

//====================================

function getRepeatDataIndex(repeatD,j) {

  var arr = []

  for(I in repeatD) {  

    arr.push(j.map((duplicate,i) => duplicate === repeatD[I] ? (i) : null)   //(i+1) for google sheet row 1 or col 1

    .filter(i => i !== null))

    }

    return arr

}