How to retrieve Mongodb child value without parents object/field name - mongodb

Question

Is there a way to query one type of child objects (child object/field with same name under different parents object/field ) directly without invoking the parents name in the find() command
For example I have
MondoDB
{
eatable.fruits.tomato
}
{
eatable.vegetables.tomato
}
Here each tomato is a parameter which have some value assigned in it, And I have tomato under two different objects/fields,
Is there a way to query and retrieve all values of tomato without using the field/object names "fruits" or "vegetables" in the find () command.

Answer 1

As of now, there is no direct way to search for child fields without knowing the parent fields but we do have the workaround. The idea is to first filter the documents by adding the constraints in find() method and then iterate over the response and print out the values of 'tomato' key where ever its present as leaf element.
Following is the example:
db.collection.find().forEach(
function processDoc(document){
let keys = Object.keys(document);
keys.forEach(
function(key){
let value = document[key];
if(typeof value === typeof Object()){
processDoc(value); // Its an embedded document, thus process it again
}else if(key == 'tomato'){
print(value);
}
}
);
}
);
Data set:
{
"_id" : ObjectId("5d63ac599d32d1c15cf5ea5e"),
"eatable" : {
"vegetables" : {
"tomato" : "veg1"
},
"fruits" : {
"tomato" : "fru1",
"banana": "fru1"
},
"misc" : {
"item" : {
"tomato" : "misc1"
}
}
}
}
{
"_id" : ObjectId("5d63ac599d32d1c15cf5ea5f"),
"eatable" : {
"fruits" : {
"tomato" : "fru2"
}
}
}
Output:
veg1
fru1
misc1
fru2