我有一个场景，在构造表单数据时，嵌套的JSON必须以线性方式序列化，因为这是服务器期望值的方式。所以，我写了一个小的递归函数来翻译JSON，就像这样:

{
   "orderPrice":"11",
   "cardNumber":"************1234",
   "id":"8796191359018",
   "accountHolderName":"Raj Pawan",
   "expiryMonth":"02",
   "expiryYear":"2019",
   "issueNumber":null,
   "billingAddress":{
      "city":"Wonderland",
      "code":"8796682911767",
      "firstname":"Raj Pawan",
      "lastname":"Gumdal",
      "line1":"Addr Line 1",
      "line2":null,
      "state":"US-AS",
      "region":{
         "isocode":"US-AS"
      },
      "zip":"76767-6776"
   }
}

变成这样:

{
   "orderPrice":"11",
   "cardNumber":"************1234",
   "id":"8796191359018",
   "accountHolderName":"Raj Pawan",
   "expiryMonth":"02",
   "expiryYear":"2019",
   "issueNumber":null,
   "billingAddress.city":"Wonderland",
   "billingAddress.code":"8796682911767",
   "billingAddress.firstname":"Raj Pawan",
   "billingAddress.lastname":"Gumdal",
   "billingAddress.line1":"Addr Line 1",
   "billingAddress.line2":null,
   "billingAddress.state":"US-AS",
   "billingAddress.region.isocode":"US-AS",
   "billingAddress.zip":"76767-6776"
}

服务器将接受这种转换格式的表单数据。

函数如下:

function jsonToFormData (inJSON, inTestJSON, inFormData, parentKey) {
    // http://stackoverflow.com/a/22783314/260665
    // Raj: Converts any nested JSON to formData.
    var form_data = inFormData || new FormData();
    var testJSON = inTestJSON || {};
    for ( var key in inJSON ) {
        // 1. If it is a recursion, then key has to be constructed like "parent.child" where parent JSON contains a child JSON
        // 2. Perform append data only if the value for key is not a JSON, recurse otherwise!
        var constructedKey = key;
        if (parentKey) {
            constructedKey = parentKey + "." + key;
        }

        var value = inJSON[key];
        if (value && value.constructor === {}.constructor) {
            // This is a JSON, we now need to recurse!
            jsonToFormData (value, testJSON, form_data, constructedKey);
        } else {
            form_data.append(constructedKey, inJSON[key]);
            testJSON[constructedKey] = inJSON[key];
        }
    }
    return form_data;
}

调用:

        var testJSON = {};
        var form_data = jsonToFormData (jsonForPost, testJSON);

我使用testJSON只是为了查看转换后的结果，因为我无法提取form_data的内容。AJAX post call:

        $.ajax({
            type: "POST",
            url: somePostURL,
            data: form_data,
            processData : false,
            contentType : false,
            success: function (data) {
            },
            error: function (e) {
            }
        });

使用jquery，你可以通过$.param(obj)简单地做到这一点。

例子: Const obj = { 描述:'Some Item'， 价格:0.00, srate:“0.00”, 颜色:红色的 ｝ Const form_obj = $.param(obj); . ajax({美元 url:“example.com”, 方法:“文章”, 数据:form_obj }) < script src = " https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js " > < /脚本>

将处理嵌套数组和对象的解决方案。有人可能会觉得有用

             function add_form_data(form_data,key,item,arr){
                if(typeof(item)==='object' && item && item.constructor===Array){
                    for(var i=0;i<item.length;i++){
                        var item2=item[i];
                        var key2=key+'[' + i +']';
                        if(arr){
                            key2=key+'[' + key2 +']';
                        }
                        add_form_data(form_data,key2,item2,true);
                    }
                }else if(typeof(item)==='object' && item){
                    for ( var key2 in item ) {
                        var item2=item[key2];
                        if(arr){
                            key2=key+'[' + key2 +']';
                        }
                        add_form_data(form_data,key2,item2,arr);
                    }
                }else{
                    form_data.append(key,item);
                }
            }

使用

            var form_data = new FormData();
            
            add_form_data(form_data,null,json_data);// provide json_data here
             
            var string_url_data=new URLSearchParams(form_data).toString();// if query string is needed

函数toFormData(o) { 返回Object.entries (o) .reduce ((d, e) = > (d.append e(…),d),新FormData ()) ｝ Var对象= { 用户名:“JohnDoe”, 文件:新文件(“foo”,“foo.txt”,{类型:“文本/普通”}) ｝ fetch (https://httpbin.org/post, { 方法:“文章”, 身体:toFormData(对象) })。Then (r => r.json()).then(console.log)

下面是一个非常简单的TypeScript实现，基于@Vladimir Novopashin和@developer033的回答。打印稿操场

type Serializeable =
    | string
    | number
    | boolean
    | null
    | Date
    | File
    | { [x: string | number]: Serializeable }
    | Array<Serializeable>;

function serialize(
    data: Serializeable,
    parentKey = '',
    formData: FormData = new FormData()
): FormData {
    if ( typeof data === 'string') {
        formData.append(parentKey, data);
    } else if ( typeof data === 'number') {
        formData.append(parentKey, data.toString());
    } else if ( typeof data === 'boolean') {
        formData.append(parentKey, data ? 'true' : 'false');
    } else if (data === null) {
        formData.append(parentKey, 'null');
    } else if (data instanceof Date) {
        formData.append(parentKey, data.toISOString());
    } else if (data instanceof File) {
        formData.append(parentKey, data);
    } else {
        // Arrays and objects
        Object.entries(data).forEach((entry: [string | number, Serializeable]) => {
            const [key, value] = entry;
            serialize(value, parentKey ? `${parentKey}[${key}]` : key.toString(), formData);
        });
    }

    return formData;
}

你可以简单地使用:

formData.append('item', JSON.stringify(item));