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node.jsfileapi

Convert response from nodejs fs to web file api

Got a package reading and parsing files in browser

<input multiple accept=".abc" name="file" id="txtFileUpload" type="file" onchange="upload(event)"/>

function upload(event) {
    var file = event.target.files[0];
    somepackage.read(file, function(error, data) {...}

I need to use the same package in nodejs

fs.readFile("somefile.abc", 'utf8' , (err, file) => {
    somepackage.read(file, function (error, data) {
   // gives error

The response from web browser api and response from node js fs is not the same. Is it possible to convert the response from node's fs so it is the same as in the browser?

Solution

  • In the browser, the file variable will be an instance of File as described in the MDN page: https://developer.mozilla.org/en-US/docs/Web/API/File

    Meaning it's a complete object with properties like name, lastModified…

    Meanwhile in Node.js the value returned by fs.readFile with the utf8 encoding will be the content of the file as a string.

    So they're indeed incompatible. Depending on what somepackage.read does with the File object, you may be able to emulate a dummy object by retrieving date info with a separate fs.stat call.

    Fortunately, projects like https://github.com/node-file-api/file-api already took care of it.

    Beware that if somepackage.read assume that the provided file is a Blob, you'll need to enhance the package mentioned above by using feature introduced very recently in Node.js 15.x : https://github.com/nodejs/node/pull/36811