使用JavaScript将PDF文件转换为Base64字符串

Question

I have a link to a local pdf file and I need that file as a base64 string. I'm programming with JavaScript. Does anybody know how I can get this string?

UPDATE:

I have to file object because I downloaded the pdf

Answer 1

Try this :-

<input id="inputFile" type="file" onchange="convertToBase64();" />

<script type="text/javascript">
    function convertToBase64() {
        //Read File
        var selectedFile = document.getElementById("inputFile").files;
        //Check File is not Empty
        if (selectedFile.length > 0) {
            // Select the very first file from list
            var fileToLoad = selectedFile[0];
            // FileReader function for read the file.
            var fileReader = new FileReader();
            var base64;
            // Onload of file read the file content
            fileReader.onload = function(fileLoadedEvent) {
                base64 = fileLoadedEvent.target.result;
                // Print data in console
                console.log(base64);
            };
            // Convert data to base64
            fileReader.readAsDataURL(fileToLoad);
        }
    }
</script>

From this

Answer 2

With Screw-FileReader & fetch

fetch('/file.pdf')
.then(res => res.blob())
.then(blob => blob.dataUrl())
.then(base64 => console.log(base64))

I could give you a few reason why you don't need the base64 string and why it's inconvenient. But i don't know why you need it... The overall reason is URL.createObjectURL and that it's ~3x larger