What Data Type Can I Use For a Boolean Value Or Null?

{
      name: 'compoundObject',
      type: 'object',
      fields: [
        {
          name: 'section',
          type: 'section',//section is another object with a string field
        },
        {
          name: 'addedField',
          type: 'string',
        },
      ],
    },

    {
      title: "Cart Items",
      name: "cartItems",
      type: "array",
      of: [
        {
          title: "Product Variants Cart",
          type: "productVariant",
        },
        {
          name: "name",
          type: "string",
        },
        {
          name: "amount",
          type: "number",
        },
      ],
    },