You should do something like:
let isMosaicMirror = false, isTreasureBox = false;
if (roles.some(r => r.name === "EXP Mosaic Mirror")) {
isMosaicMirror = true;
}
if (roles.some(r => r.name === "EXP Treasure Box")){
isTreasureBox = true;
}
let filter = wixData.filter();
if(isMosaicMirror && isTreasureBox){
filter = filter.eq("roleFilter", "expMM").or(filter.eq("roleFilter", "expTB"));
} else if(isMosaicMirror ){
filter = filter.eq("roleFilter", "expMM");
} else if(isTreasureBox ){
filter = filter.eq("roleFilter", "expTB");
}
$w("#dataset").setFilter(filter).then(r => {
//etc...
})