Promise的两种处理异步的方式

单个异步处理：

let usedMemoryPromise = fetchUsedMemeory();
usedMemoryPromise.then（data => {...}）




    function fetchUsedMemeory(){
        return new Promise( function(resolve){
            let clusterId = $("#cluster-id").val();
            invokeJsonRpc(RDS_CONFIG.APOLLO_CMDB_ENDPOINT_V3,
                "query.aggregate",
                {
                    graph: `graph g {  redisCluster: RedisCluster[ id = "${clusterId}" ];}`,
                    fields: [["redisCluster.name", "redisCluster.id", "redisCluster.used_memory"]]
                }).then(resp => {
                let usedMemory = resp.result.children[0].data["redisCluster.used_memory"];
                resolve(usedMemory);
            })
        });
    }

多个异步同时处理：

async function findXdcrRelation(state, bucketId) {
    const xdcrSourcePromise = invokeJsonRpc(RDS_CONFIG.APOLLO_CMDB_ENDPOINT_V3,
        "query.resource",
        {
            graph: `g {
                    x: CouchbaseXDCR;
                    s: CouchbaseBucket [id=${bucketId}];
                    x  ~> @source_bucket ~> s;}`,
            target: 0
        });
    const xdcrTargetPromise = invokeJsonRpc(RDS_CONFIG.APOLLO_CMDB_ENDPOINT_V3,
        "query.resource",
        {
            graph: `g {
                    x: CouchbaseXDCR;
                    s: CouchbaseBucket [id=${bucketId}];
                    x  ~> @target_bucket ~> s;}`,
            target: 0
        });
    let [xdcrSourceData, xdcrTargetData] = await Promise.all([xdcrSourcePromise, xdcrTargetPromise]);
    const hasError = (xdcrSourceData.hasOwnProperty("error") && xdcrTargetData.hasOwnProperty("error"));
    if (!hasError && (xdcrSourceData.result.length > 0 || xdcrTargetData.result.length > 0)) {
        state.hasXdcrRelation = true;
    }
}