SOURCE

let specGroup = [
    // [{key: "stock", value: 88}]
]
let goods = {
    id: 1,
    name: "荣耀手机",
    categoryId: 1,
    images: [''],
    status: 1,
    specList: [
        {id: 1, name: "颜色", params: "color", values: [
            {id: 1, spec_id: 1, spec_value: "红色"},
            {id: 3, spec_id: 1, spec_value: "黑色"}
        ]},
        {id: 2, name: "存储容量", params: "ram", values: [
            {id: 2, spec_id: 2, spec_value: "8G"},
            {id: 5, spec_id: 2, spec_value: "16G"}
        ]},
        {id: 6, name: "版本", params: "version", values: [
            {id: 15, spec_id: 6, spec_value: "官网标配"}
        ]},
        {id: 7, name: "型号", params: "model", values: [
            {id: 6, spec_id: 7, spec_value: "A号"},
            {id: 7, spec_id: 7, spec_value: "B号"},
            {id: 8, spec_id: 7, spec_value: "C号"},
            {id: 9, spec_id: 7, spec_value: "D号"},
            {id: 10, spec_id: 7, spec_value: "E号"},
            {id: 11, spec_id: 7, spec_value: "F号"},
            {id: 12, spec_id: 7, spec_value: "G号"},
            {id: 13, spec_id: 7, spec_value: "H号"},
            {id: 14, spec_id: 7, spec_value: "I号"}
        ]},
    ],
    skuList: [
        {
            id: 2259, // skuId
            spec_value_ids: [1,2],
            spec_value_key: '1_2',
            price: 100, // 价格（单位分）
            stock: 110 // 当前 sku 组合对应的库存
        },
        {
            id: 2260, // skuId
            spec_value_ids: [1,5],
            spec_value_key: '1_5',
            price: 100, // 价格（单位分）
            stock: 0 // 当前 sku 组合对应的库存
        },
        {
            id: 2260, // skuId
            spec_value_ids: [3,2],
            spec_value_key: '3_2',
            price: 100, // 价格（单位分）
            stock: 10 // 当前 sku 组合对应的库存
        },
        {
            id: 2260, // skuId
            spec_value_ids: [3,5],
            spec_value_key: '3_5',
            price: 100, // 价格（单位分）
            stock: 110 // 当前 sku 组合对应的库存
        }
    ]
}
let specNames = {};
let specValues = {};
goods.specList.map((item, index) => {
    specNames[item.id] = {
        id: item.id,
        label: item.name,
        prop: item.params
    }
    item.values.forEach((v) => {
        specValues[v.id] = v
    })
})
function groupBy(array, f) {
    const groups = {}
    array.forEach(o => {
    const group = JSON.stringify(f(o))
    groups[group] = groups[group] || []
    groups[group].push(o)
    })
    return Object.keys(groups).map(group => {
    return groups[group]
    })
}
function arrayGroupBy(list, groupId) {
    return this.groupBy(list, item => {
        return [item[groupId]]
    })
}
// 选中的规格
let checkedSpec = [
    {id: 1, spec_id: 1, spec_value: "红色"},
    {id: 2, spec_id: 2, spec_value: "8G"}
]
// if (specGroup.length > 0 ) {

// }
// 选中的规格分下组
specGroup = arrayGroupBy(checkedSpec, 'spec_id')
// 组合算法
let combination = specGroup.reduce((previous, current) => {
    let arr = [];
    previous.forEach(previous => {
        current.forEach(item => {
            let combination = previous.concat(item)
            arr.push(combination)
        })
    })
    return arr;
}, [[]])
if (combination[0].length > 0) {
    // 重新处理下生成的sku
    combination.forEach((itemArr, index) => {
        let obj = {}
        let ids = []
        itemArr.forEach((v)=>{
            ids.push(v.id)
        })
        obj.spec_value_key = ids.join('_')
        obj.spec_value_ids = ids
        obj.stock = 0
        obj.price = 0
        // 替换sku中的元素(如果找到)
        if (goods.skuList.length === 0 ) {
            goods.skuList.push(obj)
        } else {
            let skuListIndex = goods.skuList.findIndex((sku, index) => {
                return sku.spec_value_key === obj.spec_value_key
            })
            if (skuListIndex === -1) {
                goods.skuList.push(obj)
            } else {
                goods.skuList.splice(skuListIndex, 1, obj)
            }
        } 
    })
}
// 表格列头、skuData
let skuColumns = [];
let skuData = [];
goods.skuList.forEach((item, index) => {
    item.spec_value_ids.forEach((v) => {
        let specVal = specValues[v];
        let specName = specNames[specVal.spec_id];
        let key = specNames[specVal.spec_id].prop
        let value = specVal.spec_value
        item[key] = value

        // 生成列头
        if (index === 0) {
          skuColumns.push(specName)
        }
    })
})


let prevKey = [1,5,9];
let currKey = [1,5,4,9];
let res = false;

let difference = prevKey.filter(function(v){ return currKey.indexOf(v) === -1 })
console.log(difference)