Вот простой фрагмент, который возвращает массив Data
const array = [
{Cols: [], Data: [{condition_type: "1"}], title: "Environmental Condition"},
{Cols: [], Data: [{condition_type: "2"}], title: "Ventilation"},
{Cols: [], Data: [{condition_type: "3"}], title: "Thermal Comfort"},
{Cols: [], Data: [{condition_type: "4"}], title: "Internal Loads"},
{Cols: [], Data: [{condition_type: "5"}], title: "Exhaust"},
{Cols: [], Data: [{condition_type: "6"}], title: "Misc"},
]
console.log(array.map(({Data: [val]})=>val))
или если вы хотите получить прямой доступ к значениям определенных клавиш
const array = [
{Cols: [], Data: [{condition_type: "1"}], title: "Environmental Condition"},
{Cols: [], Data: [{condition_type: "2"}], title: "Ventilation"},
{Cols: [], Data: [{condition_type: "3"}], title: "Thermal Comfort"},
{Cols: [], Data: [{condition_type: "4"}], title: "Internal Loads"},
{Cols: [], Data: [{condition_type: "5"}], title: "Exhaust"},
{Cols: [], Data: [{condition_type: "6"}], title: "Misc"},
]
console.log(array.map(({Data: [{condition_type}]})=>condition_type))