JavaScript：等待遞回樹完成，其中每個遞回級別都是一個API呼叫-有解無憂

我正在嘗試使用遞回 API 呼叫構建一個 JSON 樹，但我在資料結構的流控制方面遇到了問題。如何在 BuildTree 函式堆疊結束之前阻止流？

這是部分代碼。提前致謝。

//FIRST CALL TO RETRIEVE THE ROOT
function callFW() {
    d3.json(url, function(data) { //?<----- api call
            Tree["uid"] = data.request.uid
            Tree["hid"] = data.firmware.meta_data.hid
            Tree["size"] = data.firmware.meta_data.size
            Tree["children"] = [];
            
            BuildTree(data.firmware.meta_data.included_files,Tree["children"])
            //WAIT FOR BUILDTREE
            console.log(Tree)
        } 
}

BuildTree 函式是這樣的：

async function BuildTree(included_files, fatherNode){ 
        if( included_files.length > 0){
            promises = [];

            included_files.forEach(function(item) {
                url = endpoint "file_object/" item "?summary=true";
                promises.push(axios.get(url));
            });

            Promise.all(promises).then(function (results) {
                results.forEach(function (response) {
                    
                    var node = {}
                    node["uid"]= response.data.request.uid
                    node["hid"]= response.data.file_object.meta_data.hid
                    node["size"] = response.data.file_object.meta_data.size
                    node["children"] = []

                    fatherNode.push(node)

                    BuildTree(response.data.file_object.meta_data.included_files, node["children"])
                    


                });
            });
        }
    }

uj5u.com熱心網友回復：

您async無緣無故地使用關鍵字，因為您沒有await在函式內部使用。你也可以使用它:)

async function BuildTree(included_files, fatherNode) {
    if (included_files.length > 0) {
        let promises = [];

        included_files.forEach(function (item) {
            url = endpoint   "file_object/"   item   "?summary=true";
            promises.push(axios.get(url));
        });

        const results = await Promise.all(promises);

        for(let response of results){

            var node = {}
            node["uid"] = response.data.request.uid
            node["hid"] = response.data.file_object.meta_data.hid
            node["size"] = response.data.file_object.meta_data.size
            node["children"] = []

            fatherNode.push(node)

            await BuildTree(response.data.file_object.meta_data.included_files, node["children"]);
        };
    }
};

然后你可以簡單地await BuildTree：

function callFW() {
    d3.json(url, async function(data) {
            Tree["uid"] = data.request.uid
            Tree["hid"] = data.firmware.meta_data.hid
            Tree["size"] = data.firmware.meta_data.size
            Tree["children"] = [];
            
            await BuildTree(data.firmware.meta_data.included_files,Tree["children"]);

            console.log(Tree)
        })
}

轉載請註明出處，本文鏈接：https://www.uj5u.com/yidong/326799.html

標籤：javascript 异步递归异步等待树

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