/TypeScript/Mongo count elements in array

Mongo count elements in array

> db.mycollection.insert({'foo':[1,2,3,4]})
> db.mycollection.insert({'foo':[5,6,7]})

> db.mycollection.aggregate([{$project: { count: { $size:"$foo" }}}])
{ "_id" : ObjectId("5314b5c360477752b449eedf"), "count" : 4 }
{ "_id" : ObjectId("5314b5c860477752b449eee0"), "count" : 3 }

Source: stackoverflow.com

Mongo count elements in array

{ $size: <expression> }

Source: docs.mongodb.com

Mongodb count array size

db.inventory.aggregate([
   {
      $project: {
         item: 1,
         numberOfColors: { $cond: { if: { $isArray: "$colors" }, then: { $size: "$colors" }, else: "NA"} }
      }
   }
] )

Source: docs.mongodb.com

Similar codes

0 vote366 views1 answer
Print query from get_posts wordpress
TypeScript
0 vote314 views1 answer
Mongodb nest.js
TypeScript
0 vote438 views1 answer
Request exceeded the limit of 10 internal redirects due to probable configuration error
TypeScript
0 vote365 views3 answers
Typescript optional parameters
TypeScript
0 vote326 views1 answer
React Draft Wysiwyg typescript
TypeScript
5 votes333 views2 answers
Array.prototype.map() expects a return value from arrow function array-callback-return react
TypeScript
0 vote330 views1 answer
Typescript key as string
TypeScript
5 votes352 views2 answers
Formgroup check if valid
TypeScript
0 vote317 views1 answer
Python requests exceptions
TypeScript
0 vote353 views1 answer
Angular how to use observable object async
TypeScript