How does file API work internally in JavaScript?

        // Example of using the File API with a FileReader
        document.getElementById('fileInput').addEventListener('change', function(event) {
            const file = event.target.files[0]; // Get the selected file
            const reader = new FileReader(); // Create a new FileReader instance

            reader.onload = function(e) {
                const content = e.target.result; // Get the file content
                console.log(content); // Display file content in console
            };

            reader.readAsText(file); // Read the file as text
        });