$regex to find a document in mongodb that contains a string -

i working on db query in mongo need query document regular expressing string field(fieldtoquery).

the datastructure like

{      fieldtoquery : "4052577300",      someotherfield : "some value",      ...      ... } 

i have value "804052577300", using have query above document.

how achieve same using $regex operator?

update:

i need ends regex in mongo.

you sort of reverse regex query create regex using fieldtoquery value , test against query value:

var value = "804052577300";         db.test.find({     $where: "new regexp(this.fieldtoquery + '$').test('" + value + "');"  }); 

the $where operator allows execute arbitrary javascript against each doc in collection; this current doc, , truthy result of expression determines whether doc should included in result set.

so in case, new regexp built each doc's fieldtoquery field $ @ end anchor search end of string. test method of regex called test whether value string matches regex.

the $where string evaluated server-side, value's value must evaluated client-side directly including value $where string.

note $where queries can quite slow can't use indexes.