Function load_bigint 

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

The static Atomics.load() method returns a value at a given position in the array.

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

MDN documentation