React - Axios POST form data with files and strings

Question

I had to create Axios POST where the body type is form-data. Some of keys are strings, and some are files. Postman request:

How to add upload buttons to fetch files into state, and how to make Axios request?

Answer 1

import React, { Component } from 'react';
import axios from "axios";

class FileUpload extends Component {

    // API Endpoints
    custom_file_upload_url = `YOUR_API_ENDPOINT_SHOULD_GOES_HERE`;


    constructor(props) {
        super(props);
        this.state = {
            image_file: null,
            image_preview: '',
        }
    }

    // Image Preview Handler
    handleImagePreview = (e) => {
        let image_as_base64 = URL.createObjectURL(e.target.files[0])
        let image_as_files = e.target.files[0];

        this.setState({
            image_preview: image_as_base64,
            image_file: image_as_files,
        })
    }

    // Image/File Submit Handler
    handleSubmitFile = () => {

        if (this.state.image_file !== null){

            let formData = new FormData();
            formData.append('customFile', this.state.image_file);
            // the image field name should be similar to your api endpoint field name
            // in my case here the field name is customFile

            axios.post(
                this.custom_file_upload_url,
                formData,
                {
                    headers: {
                        "Authorization": "YOUR_API_AUTHORIZATION_KEY_SHOULD_GOES_HERE_IF_HAVE",
                        "Content-type": "multipart/form-data",
                    },                    
                }
            )
            .then(res => {
                console.log(`Success` + res.data);
            })
            .catch(err => {
                console.log(err);
            })
        }
    }


    // render from here
    render() { 
        return (
            <div>
                {/* image preview */}
                <img src={this.state.image_preview} alt="image_preview"/>

                {/* image input field */}
                <input
                    type="file"
                    onChange={this.handleImagePreview}
                />
                <label>Upload file</label>
                <input type="submit" onClick={this.handleSubmitFile} value="Submit"/>
            </div>
        );
    }
}

export default FileUpload;

Answer 2

Simply trigger a method in onChange event on input of type "file" and send to server with "multipart/form-data" format:

<Input id="file" type="file" onChange={this.uploadFile} />

        let formData = new FormData();
        /*
          Iteate over any file sent over appending the files
          to the form data.
        */
        for( var i = 0; i < this.files.length; i++ ){
          let file = this.files[i];
          formData.append('files[' + i + ']', file);
        }
        /*
          Make the request to the POST /select-files URL
        */
        axios.post( '/select-files',
          formData,
          {
            headers: {
                'Content-Type': 'multipart/form-data'
            }
          }
        ).then(function(){
          console.log('SUCCESS!!');
        })
        .catch(function(){
          console.log('FAILURE!!');
        });