diff.js

function diff(arr1, arr2) {
    return arr1.filter(x => arr2.includes(x));
}

const arr1 = [
    34242,
    33030,
    34241,
    27118,
    34152,
    33171,
    27069,
    29001,
    8073,
    27069,
    9658,
    9050,
    27071,
    11037,
    11029,
    11031,
    11032,
    13122,
    13170,
    13168,
    13123,
    27099,
    25563,
    26494,
    5120,
    4752,
    15300,
    23129,
    26947,
    26915,
    24462,
    27035,
    24452,
    26958,
    27068,
    27073,
    17024,
    17023,
    5282,
    15299,
    17012,
    10284,
    17013,
    25729,
    17014,
    10283,
    26912,
    33067,
    27070,
    25755,
    23359,
    26209,
    23361,
    23382,
    5283,
    15301,
    25488,
    17011,
    25754,
    27074,
    27098,
    25737,
    25734,
    25618,
    34178,
    25735,
    22027,
    26612,
    24308,
    27077,
    25560,
    27067,
    27072,
    32002,
    32001,
    32003,
    25617,
    21262,
    27076,
    34117,
    26892,
    27104
]

const arr2 = [
    26982,
    14056,
    21253,
    25118,
    21420,
    33164,
    33165,
    34121,
    4224,
    23129,
    33073,
    27104,
    8086,
    26916,
    34217,
    25169
]

console.log(diff(arr1, arr2))