SOURCE

var list = [
    {
        title: '这是答案0-1',
        type: 'y'
    },
    {
        title: '这是答案0-2',
        type: 'y'
    },
    {
        title: '这是问题1',
        type: 'x'
    },
    {
        title: '这是答案1',
        type: 'y'
    },
    {
        title: '这是答案2',
        type: 'y'
    },
    {
        title: '这是答案3',
        type: 'y'
    },
    {
        title: '这是答案4',
        type: 'y'
    },
    {
        title: '这是问题2',
        type: 'x'
    },
    {
        title: '这是答案2-1',
        type: 'y'
    },
    {
        title: '这是答案2-2',
        type: 'y'
    },
    {
        title: '这是答案2-3',
        type: 'y'
    },
    {
        title: '这是答案2-4',
        type: 'y'
    },
    {
        title: '这是问题3',
        type: 'x'
    },
    {
        title: '这是答案3-1',
        type: 'y'
    }
]

function fn() {
    let arr_ind = []
    for (let x = 0; x < list.length; x++) {
        if (list[x].type === 'x') {
            arr_ind.push(x)
        }
    }
    let arr = []
    for (let y = 0; y < arr_ind.length; y++) {
        if (arr_ind[y] !== 0 && y === 0) {
            arr.push({
                title: null,
                list: list.slice(0, arr_ind[y])
            })
        } else {
            arr.push({
                title: list[arr_ind[y]].title,
                list: list.slice(arr_ind[y] + 1, arr_ind[y + 1])
            })
        }
    }
}
fn()