SOURCE

const generator  = function * (arr, k) {
    while (k--) {
        const toSwitchIndex = Math.floor(Math.random() * arr.length)
        const temp = arr[toSwitchIndex]
        arr[toSwitchIndex] = arr[arr.length - 1]
        arr[arr.length - 1] = temp
        yield arr.pop()
    }
}

const gen = generator(['a', 'b', 'c'], 3)
console.log(...gen)