Function store_bigint 

pub fn store_bigint<T>(
    typed_array: &T,
    index: u32,
    value: i64,
) -> Result<i64, JsValue>
where
    T: TypedArray + ErasableGenericBorrow<Int32Array>,

The static Atomics.store() method stores a given value at the given position in the array and returns that value.

This method is used to operate on a BigInt64Array or a BigUint64Array.

MDN documentation