MongoDB $bitsAllClear with BinData - how it works? - mongodb

Question

Does anyone knows how the mongodb $bitsAllClear works?
I ready the document from https://docs.mongodb.com/manual/reference/operator/query/bitsAllClear/ i am trying to understand how can i create a BinData from a bitmask
For example the documentation says:
(the binary representation of BinData(0, "ID==") is 00010100.
How can i transform the 00010100 to binary to insert in the document? Is there any online converted to try?

Answer 1

(the binary representation of BinData(0, "ID==") is 00010100.
This example looks incorrect to me. BinData takes a base64 encoded string as its second argument, and the base64 encoding of 00010100 is FA==. Other examples on that same page look correct, so I suspect it's a typo.
In node, you can do the conversion from a binary string to base64 like so:
const hexString = parseInt('00010100', 2).toString(16);
Buffer.from(hexString, 'hex').toString("base64") // FA==
Online tool to test out encodings here -> https://cryptii.com/pipes/binary-to-base64