Code brushes for GitHub Copilot

GitHub Copilot is incredible, and if you check what's happening in the preview released as the Copilot Labs extension it will only get more amazing.

Check this out:

Let's start with a basic JavaScript that checks a string length and reports when it is empty. One with an obvious mistake, as we use a single = instead of the type safe ===. This will always report the string as empty.

if (str.length = 0) {
    console.error('String is empty');
}

Using the Fix bugs brush, this is rectified.

if (str.length === 0) {
    console.error('String is empty');
}

Using the Clean brush also adds reporting when the string is not empty.

if (str.length === 0) {
    console.error('String is empty');
} else {
    console.log('String is not empty');
}

Using the List steps brush adds comments for step (sure, this is redundant, but it also works for much more complex code).

// check the length of the string
if (str.length === 0) {
    // if length is 0, print 'String is empty' 
    console.error('String is empty');
} else {
    // if length is not 0, print 'String is not empty'
    console.log('String is not empty');
}

Using Make robust adds error reporting instead of logging and an extra check to make sure that str is really a String and not an empty Array.

function test(str) {
    if (str.length === 0) {
        throw new Error('String is empty');
    } else if (typeof str !== 'string') {
        throw new Error('It is not a string');
    } else {
        console.log('String is not empty');
    }
}

The Add types brush does exactly that.

/**
 * @param {string} str
 * @returns {string}
 */
function test(str) {
    if (str.length === 0) {
        throw new Error('String is empty');
    } else if (typeof str !== 'string') {
        throw new Error('It is not a string');
    } else {
        console.log('String is not empty');
    }
}

You can also define custom brushes and there are more to come.