Database
[{"_id":"61c01098bc29520008efc00f","name":"codedump","employments":[{"type":"PERMANENT","salary":1000000000},{"type":"TEMP","salary":1000000000},{"type":"PART_TIME","salary":1000000000},{"type":"INVESTMENT","salary":5},]}]
Query
db.collection.update({},[{$set:{employments:{$cond:[{$in:["INVESTMENT","$employments.type"]},{$map:{input:"$employments",in:{$cond:[{$eq:["$$this.type","INVESTMENT"]},{type:"$$this.type",salary:10000},"$$this"]}}},{$concatArrays:["$employments",[{type:"INVESTMENT",salary:10000}]]}]}}}])