The sheet has multiple rows joined by ";" and I need to expand the strings and also keep the table IDs.

function expand_joins(range) {
  var output2 = [];
  for(var i = 0, iLen = range.length; i < iLen; i  ) {
    var s = range[i][1].split(";");    
    for(var j = 0, jLen = s.length; j < jLen; j  ) {
      var output1 = []; 
      for(var k = 0, kLen = range[0].length; k < kLen; k  ) {
        if(k == 1) {
          output1.push(s[j]);
        } else {
          output1.push(range[i][k]);
        }
      }
      output2.push(output1);
    }    
  }
  return output2;
}

Desirable Output: two columns

CodePudding user response：

UPDATED

If you're using the V8 runtime (new IDE) you can try the following:

function expandJoins(range) {
    return range
        .map(row => row[1]
            .split(';')
            .map(splitItem => [row[0], splitItem])
        )
        .flat();
}