Upload and validation - Typescript and angular

Question

This is just a feature of an app to check the file extension and size before uploading. No need for reading data. Examples will be appreciated. Thanks

Answer 1

this can be achieved by normal javascript too. typescript is a superset of javascript. you could write a function to check file size and extension. before that, you need to send an event to your function from view.

so in angular, you can try like

<input type="file" (change)="fileEvent($event)" >

and in typescript, you can write a function to check event like

 fileEvent(e) {

    /// get list of files
    let file_list = e.target.files;

    /// go through the list of files
    for (let i = 0, file; file = file_list[i]; i++) {

        let sFileName = file.name;
        let sFileExtension = sFileName.split('.')[sFileName.split('.').length - 1].toLowerCase();
        let iFileSize = file.size;
        let iConvert = (file.size / 1048576).toFixed(2);

        /// OR together the accepted extensions and NOT it. Then OR the size cond.
        /// It's easier to see this way, but just a suggestion - no requirement.
        if (!(sFileExtension === "pdf" ||
              sFileExtension === "doc" ||
              sFileExtension === "docx") || iFileSize > 10485760) { /// 10 mb
            txt = "File type : " + sFileExtension + "\n\n";
            txt += "Size: " + iConvert + " MB \n\n";
            txt += "Please make sure your file is in pdf or doc format and less than 10 MB.\n\n";
            alert(txt);
        }
    }
}