<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Create a JavaScript function to encode a given string with Base64 encoding.
myString = "Hello World!"<|im_end|>
<|im_start|>assistant
function encodeBase64(myString) {
    return btoa(myString);
}
var myStringEncoded = encodeBase64(myString);
console.log(myStringEncoded);<|im_end|>
