I think this is what you're looking for. 3rd result for "Javascript type coercion": https://2ality.com/2019/10/type-coercion.html
Sorry for trying to help I guess, good luck.
This is the question that you asked and that I answered.
If you're looking for the language specification, it's here (first result for "Javascript specification"): https://www.ecma-international.org/ecma-262/11.0/index.html#...