将数组附加到 FormData 并通过 AJAX 发送

您也可以通过 FormData 以这种方式发送数组：

var formData = 新的 FormData; var arr = ['this', 'is', 'an', 'array']; for (var i = 0; i < arr.length; i++) { formData.append('arr[]', arr[i]); } console.log(...formData);

因此，您可以像使用简单的 HTML 表单一样编写 arr[]。如果是 PHP，它应该可以工作。

您可能会发现这篇文章很有用：How to pass an array within a query string?

---

你有几个选择：

将其转换为 JSON 字符串，然后在 PHP 中解析（推荐）

JS

var json_arr = JSON.stringify(arr);

PHP

$arr = json_decode($_POST['arr']);

或者使用@Curios 的方法

通过 FormData 发送数组。

不推荐：使用序列化数据，然后在 PHP 中反序列化

JS

// Use <#> or any other delimiter you want
var serial_arr = arr.join("<#>"); 

PHP

$arr = explode("<#>", $_POST['arr']);

---

打字稿版本：

export class Utility {      
    public static convertModelToFormData(model: any, form: FormData = null, namespace = ''): FormData {
        let formData = form || new FormData();
        let formKey;

        for (let propertyName in model) {
            if (!model.hasOwnProperty(propertyName) || !model[propertyName]) continue;
            let formKey = namespace ? `${namespace}[${propertyName}]` : propertyName;
            if (model[propertyName] instanceof Date)
                formData.append(formKey, model[propertyName].toISOString());
            else if (model[propertyName] instanceof Array) {
                model[propertyName].forEach((element, index) => {
                    const tempFormKey = `${formKey}[${index}]`;
                    this.convertModelToFormData(element, formData, tempFormKey);
                });
            }
            else if (typeof model[propertyName] === 'object' && !(model[propertyName] instanceof File))
                this.convertModelToFormData(model[propertyName], formData, formKey);
            else
                formData.append(formKey, model[propertyName].toString());
        }
        return formData;
    }
}

使用：

let formData = Utility.convertModelToFormData(model);

---

这是一个老问题，但我最近在发布对象和文件时遇到了这个问题。我需要能够发布一个对象，其子属性也是对象和数组。

下面的函数将遍历一个对象并创建正确的 formData 对象。

// formData - instance of FormData object
// data - object to post
function getFormData(formData, data, previousKey) {
  if (data instanceof Object) {
    Object.keys(data).forEach(key => {
      const value = data[key];
      if (value instanceof Object && !Array.isArray(value)) {
        return this.getFormData(formData, value, key);
      }
      if (previousKey) {
        key = `${previousKey}[${key}]`;
      }
      if (Array.isArray(value)) {
        value.forEach(val => {
          formData.append(`${key}[]`, val);
        });
      } else {
        formData.append(key, value);
      }
    });
  }
}

这将转换以下 json -

{
  name: 'starwars',
  year: 1977,
  characters: {
    good: ['luke', 'leia'],
    bad: ['vader'],
  },
}

进入以下FormData

 name, starwars
 year, 1977
 characters[good][], luke
 characters[good][], leia
 characters[bad][], vader

---

将所有类型输入添加到 FormData

const formData = new FormData();
for (let key in form) {
    Array.isArray(form[key])
        ? form[key].forEach(value => formData.append(key + '[]', value))
        : formData.append(key, form[key]) ;
}

---

这是 convertModelToFormData 的另一个版本，因为我需要它也能够发送文件。

实用程序.js

const Utility = {
  convertModelToFormData(val, formData = new FormData, namespace = '') {
    if ((typeof val !== 'undefined') && val !== null) {
      if (val instanceof Date) {
        formData.append(namespace, val.toISOString());
      } else if (val instanceof Array) {
        for (let i = 0; i < val.length; i++) {
          this.convertModelToFormData(val[i], formData, namespace + '[' + i + ']');
        }
      } else if (typeof val === 'object' && !(val instanceof File)) {
        for (let propertyName in val) {
          if (val.hasOwnProperty(propertyName)) {
            this.convertModelToFormData(val[propertyName], formData, namespace ? `${namespace}[${propertyName}]` : propertyName);
          }
        }
      } else if (val instanceof File) {
        formData.append(namespace, val);
      } else {
        formData.append(namespace, val.toString());
      }
    }
    return formData;
  }
}
export default Utility;

我的客户端代码.js

import Utility from './utility'
...
someFunction(form_object) {
  ...
  let formData = Utility.convertModelToFormData(form_object);
  ...
}

---

下一个版本适用于包含一系列简单值的模型：

function convertModelToFormData(val, formData = new FormData(), namespace = '') {
    if((typeof val !== 'undefined') && (val !== null)) {
        if(val instanceof Date) {
            formData.append(namespace, val.toISOString());
        } else if(val instanceof Array) {
            for(let element of val) {
                convertModelToFormData(element, formData, namespace + '[]');
            }
        } else if(typeof val === 'object' && !(val instanceof File)) {
            for (let propertyName in val) {
                if(val.hasOwnProperty(propertyName)) {
                    convertModelToFormData(val[propertyName], formData, namespace ? namespace + '[' + propertyName + ']' : propertyName);
                }
            }
        } else {
            formData.append(namespace, val.toString());
        }
    }
    return formData;
}

---

如果您有嵌套对象和数组，则填充 FormData 对象的最佳方法是使用递归。

function createFormData(formData, data, key) {
    if ( ( typeof data === 'object' && data !== null ) || Array.isArray(data) ) {
        for ( let i in data ) {
            if ( ( typeof data[i] === 'object' && data[i] !== null ) || Array.isArray(data[i]) ) {
                createFormData(formData, data[i], key + '[' + i + ']');
            } else {
                formData.append(key + '[' + i + ']', data[i]);
            }
        }
    } else {
        formData.append(key, data);
    }
}

---

基于@YackY 回答较短的递归版本：

function createFormData(formData, key, data) {
    if (data === Object(data) || Array.isArray(data)) {
        for (var i in data) {
            createFormData(formData, key + '[' + i + ']', data[i]);
        }
    } else {
        formData.append(key, data);
    }
}

使用示例：

var data = {a: '1', b: 2, c: {d: '3'}};
var formData = new FormData();
createFormData(formData, 'data', data);

发送数据：

data[a]=1&
data[b]=2&
data[c][d]=3

---

将三种格式的 Data 转换为 FormData ：

1. 单个值，如字符串、数字或布尔值

 let sampleData = {
  activityName: "Hunting3",
  activityTypeID: 2,
  seasonAssociated: true, 
};

2. 数组是对象数组

let sampleData = {
   activitySeason: [
    { clientId: 2000, seasonId: 57 },
    { clientId: 2000, seasonId: 57 },
  ],
};

3. 持有键值对的对象

let sampleData = {
    preview: { title: "Amazing World", description: "Here is description" },
};

使我们的生活变得轻松的那些：

function transformInToFormObject(data) {
  let formData = new FormData();
  for (let key in data) {
    if (Array.isArray(data[key])) {
      data[key].forEach((obj, index) => {
        let keyList = Object.keys(obj);
        keyList.forEach((keyItem) => {
          let keyName = [key, "[", index, "]", ".", keyItem].join("");
          formData.append(keyName, obj[keyItem]);
        });
      });
    } else if (typeof data[key] === "object") { 
      for (let innerKey in data[key]) {
        formData.append(`${key}.${innerKey}`, data[key][innerKey]);
      }
    } else {
      formData.append(key, data[key]);
    }
  }
  return formData;
}

示例：输入数据

let sampleData = {
  activityName: "Hunting3",
  activityTypeID: 2,
  seasonAssociated: true,
  activitySeason: [
    { clientId: 2000, seasonId: 57 },
    { clientId: 2000, seasonId: 57 },
  ],
  preview: { title: "Amazing World", description: "Here is description" },
};

输出表格数据：

activityName: Hunting3
activityTypeID: 2
seasonAssociated: true
activitySeason[0].clientId: 2000
activitySeason[0].seasonId: 57
activitySeason[1].clientId: 2000
activitySeason[1].seasonId: 57
preview.title: Amazing World
preview.description: Here is description

---

我已经修复了打字稿版本。对于 javascript，只需删除类型定义。

  _getFormDataKey(key0: any, key1: any): string {
    return !key0 ? key1 : `${key0}[${key1}]`;
  }
  _convertModelToFormData(model: any, key: string, frmData?: FormData): FormData {
    let formData = frmData || new FormData();

    if (!model) return formData;

    if (model instanceof Date) {
      formData.append(key, model.toISOString());
    } else if (model instanceof Array) {
      model.forEach((element: any, i: number) => {
        this._convertModelToFormData(element, this._getFormDataKey(key, i), formData);
      });
    } else if (typeof model === 'object' && !(model instanceof File)) {
      for (let propertyName in model) {
        if (!model.hasOwnProperty(propertyName) || !model[propertyName]) continue;
        this._convertModelToFormData(model[propertyName], this._getFormDataKey(key, propertyName), formData);
      }
    } else {
      formData.append(key, model);
    }

    return formData;
  }

---

JavaScript 代码：

var formData = new FormData();
let arr = [1,2,3,4];
formData.append('arr', arr);

php上的输出：

$arr = $_POST['arr']; ===>  '1,2,3,4'

解决方案php代码：

$arr = explode(",", $_POST['arr']); ===> [1,2,3,4]

---

就我而言，我得到了

{
    "category": [
        "Incorrect type. Expected pk value, received str."
    ]
}

错误所以

对于谁使用 React（前端）和 Django DRF（后端）：

const category = [1,2,3,4,5]
formData.append("category", JSON.stringify(category));

import json
from .serializers import ArticleSerializer
from rest_framework.response import Response

class ArticleListCreateView(ListCreateAPIView):
    permission_classes = (
        IsSuperuserOrReadOnly,
        IsAutherOrReadOnly,
    )
    serializer_class = ArticleSerializer
    model = Article
    queryset = Article.objects.filter(article_honor='a', status='p')


    def create(self, request, *args, **kwargs):
        data = request.data
        article = Article('set all argumenst')
        
        image = request.data['image']
        # save image in local

        article.save()
        categorys = json.loads(data['category'])
        for catID in categorys:
            cat = Category.objects.get(id=catID)
            article.category.add(cat)

        article.save()

        return Response(ArticleSerializer(article).data)

---

简单的方法：

data.map(dt=>formdata.append("name",dt))

我试过了，效果很好

---