Take a look at https://www.w3schools.com/nodejs/nodejs_mysql_insert.asp the section " Insert Multiple Records"
In it the data is an array of arrays ie instead of [{...},{...}] they use [[...],[...]] then only use one ? in the insert
Take a look at https://www.w3schools.com/nodejs/nodejs_mysql_insert.asp the section " Insert Multiple Records"
In it the data is an array of arrays ie instead of [{...},{...}] they use [[...],[...]] then only use one ? in the insert