Firestore query documents startsWith a string

Question

Is it possible to query a firestore collection to get all document that starts with a specific string?

I have gone through the documentation but do not find any suitable query for this.

Answer 1

You can but it's tricky. You need to search for documents greater than or equal to the string you want and less than a successor key.

For example, to find documents containing a field 'foo' staring with 'bar' you would query:

db.collection(c)     .where('foo', '>=', 'bar')     .where('foo', '<', 'bas'); 

This is actually a technique we use in the client implementation for scanning collections of documents matching a path. Our successor key computation is called by a scanner which is looking for all keys starting with the current user id.

Answer 2

same as answered by Gil Gilbert. Just an enhancement and some sample code. use String.fromCharCode and String.charCodeAt

var strSearch = "start with text here"; var strlength = strSearch.length; var strFrontCode = strSearch.slice(0, strlength-1); var strEndCode = strSearch.slice(strlength-1, strSearch.length);  var startcode = strSearch; var endcode= strFrontCode + String.fromCharCode(strEndCode.charCodeAt(0) + 1); 

then filter code like below.

db.collection(c) .where('foo', '>=', startcode) .where('foo', '<', endcode); 

Works on any Language and any Unicode.

Warning: all search criteria in firestore is CASE SENSITIVE.