jQuery中异步问题：数据传递

最近写一个新页面，涉及到异步问题，为了获得异步过程中的数据，以下分享两种方法；

两种方法一句话总结：

方法一，Http请求后调用.then实现response的数据同步，然后根据resp接着处理；

方法二，使用ES6中的Promise语法糖，实现异步等待resp；

方法一的代码：

其中invokeJsonRpc(RDS_CONFIG.APOLLO_CMDB_ENDPOINT_V3, "query.aggregate", queryParams)会发生一次HTTP请求

$("#submitFlushAll").on("click",function () {
        let clusterId = $("#cluster-id").val();
        const queryParams = {
            graph: `graph g {  redisCluster: RedisCluster[ id = "${clusterId}" ];}`,
            fields: [["redisCluster.name", "redisCluster.id", "redisCluster.used_memory"]]
        };
        invokeJsonRpc(RDS_CONFIG.APOLLO_CMDB_ENDPOINT_V3, "query.aggregate", queryParams).then(resp =>{
            let usedMemory = resp.result.children[0].data["redisCluster.used_memory"];
            let clusterName = $("#cluster-name").val();
            let details = {
                usedMemory : usedMemory,
                clusterName : clusterName,
            };
            let request = {
                title: `Redis清除${clusterName}的所有数据`,
                applicant: $("#username").val(),
                projectId: Number($("#project-id").val()),
                createTime: moment().format("YYYY-MM-DD HH:mm:ss"),
                resourceType: REDIS_JIGSAW_RESOURCE_TYPE,
                operationType: "redis_flush_all",
                resource: Number($("#resource-id").val()),
                sensitive: false,
                audit: true,
                carbonCopy: null,
                details: JSON.stringify(details),
                extension: null
            };
            submitJigsawWorkorder(request);
        });

方法二的代码：

注意Promise容器的构造，以及点击事件的处理函数为异步；

    $("#submitFlushDatabase").on("click", async function () {
        let clusterId = $("#cluster-id").val();
        let usedMemoryPromise = fetchUsedMemeory(clusterId);
        let usedMemory = await Promise.all([usedMemoryPromise]);
        let databaseNumber = $("#inputDatabaseNumber").val();
        let clusterName = $("#cluster-name").val();
        let details = {
            databaseNumber : databaseNumber,
            clusterName : clusterName,
            usedMemory : usedMemory,
        };
        let request = {
            title: `Redis清除指定DB，指定DB：${databaseNumber}`,
            applicant: $("#username").val(),
            projectId: Number($("#project-id").val()),
            createTime: moment().format("YYYY-MM-DD HH:mm:ss"),
            resourceType: REDIS_JIGSAW_RESOURCE_TYPE,
            operationType: "redis_flush_database",
            resource: Number($("#resource-id").val()),
            sensitive: false,
            audit: true,
            carbonCopy: null,
            details: JSON.stringify(details),
            extension: null
        };
        submitJigsawWorkorder(request);
    });

    async function fetchUsedMemeory(clusterId) {
        const queryParams = {
            graph: `graph g {  redisCluster: RedisCluster[ id = "${clusterId}" ];}`,
            fields: [["redisCluster.name", "redisCluster.id", "redisCluster.used_memory"]]
        };
        let resp = await invokeJsonRpc(RDS_CONFIG.APOLLO_CMDB_ENDPOINT_V3, "query.aggregate", queryParams);
        let usedMemory = resp.result.children[0].data["redisCluster.used_memory"];
        return usedMemory;
    }

两种方法的比较：使用Promise语法糖会使得代码结构性更加清晰，易读。

Promise学习可以参考这个链接：https://blog.csdn.net/major_zhang/article/details/79154287