FlavienBusseuil

const filters = {
    filter1,
    filter2,
    ...(condition && { filter3 }),
    filter4,
};

db.collection.find(filters);

FlavienBusseuil

const filters = Object.assign(
    ...[
        { filter1 },
        { filter2 },
	condition && { filter3 },
	{ filter4 },
    ].filter(Boolean),
);

db.collection.find(filters);

FlavienBusseuil

const filters = { filter1, filter2 }
	|> f => condition ? { ...f, filter3 } : f
	|> f => { ...f, filter4 };

db.collection.find(filters);

FlavienBusseuil

const filters = {
    filter1: value1,
    filter2: value2,
};

if (condition) {
    filters["filter3"] = value3;
}

filters["filter4"] = value4;

FlavienBusseuil

const filters = {
    filter1,
    filter2,
    ...(condition ? { filter3 } : {}),
    filter4,
};

db.collection.find(filters);

FlavienBusseuil

/* Start initializing aggregation stages based on condition */
const aggregationStages = [
    stage1,
    stage2,
];

if (condition) {
    aggregationStages.push(stage3);
}

FlavienBusseuil

const aggregationStages = [
    stage1,
    stage2,
    condition && stage3
    stage4,
].filter(Boolean);

db.collection.aggregate(aggregationStages);