https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView/setBigInt64
DataView.prototype.setBigInt64() - JavaScript | MDN
The setBigInt64() method of DataView instances takes a BigInt and stores it as a 64-bit signed integer in the 8 bytes starting at the specified byte offset of...
dataviewprototypejavascriptmdn