How to access array within a struct within an array?

Question

I have a public array of structs. Each struct has a fixed-length array inside of it. How do I go about accessing a specific struct's array member via web3? The contract is compiling, but when I use the public array's getter function, it leaves the array member out.

Solidity:

pragma solidity ^0.4.21;

contract Foo {
    struct Bar {
        bytes32 a;
        uint8[9] b;
    }

    Bar[] public bars;

    function add(bytes32 _a, uint8[9] _b) public {
        bars.push(Bar(_a, _b));
    }
}

web3:

let foo = await Foo.new();
await foo.add("banana", [1, 1, 2, 3, 5]);
let bar = await foo.bars(0);
assert.equal(foo[0], "banana");
assert.equal(foo[1], [1, 1, 2, 3, 5]); // fails, returns undefined

Answer 1

One way to solve this is to create a custom getter function to expose the array within the struct.

Solidity:

pragma solidity ^0.4.21;

contract Foo {
    struct Bar {
        bytes32 a;
        uint8[9] b;
    }

    Bar[] public bars;

    function add(bytes32 _a, uint8[9] _b) public {
        bars.push(Bar(_a, _b));
    }

    function getBarBs(uint256 _index) public returns (uint8[9]) {
        return bars[_index].b;
    }
}

web3:

let bs = await foo.getBarBs(0);
assert.equal(bs, [1, 1, 2, 3, 5]); // succeeds!