Hello, checkiomates🐱‍👤!

This week, we look back at the Origin Story of JavaScript and how it went from a toy language to a global force, analyze the State of GitHub in 2025 where AI and TypeScript are leading massive growth, and dive into a fun article about solving the New York Times Pips puzzle. Our mission challenges your precision logic by asking you to validate credit card numbers using the specialized Luhn algorithm.

💡TIP

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🏁MISSION

Luhn Algorithm: Credit Card Checker by freeman_lex -

Use Luhn algorithm to validate credit card numbers. Every credit card number is given as a string and has a correct form of four four-digit blocks, separated by single whitespace.

assert.strictEqual(checker("4137 8947 1175 5904"), true);
assert.strictEqual(checker("5468 1234 5678 9123"), false);
assert.strictEqual(checker("4539 1488 0343 6467"), true);

📖ARTICLES

The Origin Story of JavaScript -

Annie takes us all the way back to the start of the Web in the early 90s and walks us through the conditions and advancements that enabled JavaScript to take off, all the way through to our modern framework-oriented, tool-rich ecosystem.

TypeScript Leaps to #1 Most Used Language on GitHub -

As part of this week’s GitHub Universe event, GitHub released its annual report of activity on the platform. A year ago, Python jumped to #1, pushing JavaScript to #3, but this year TypeScript takes the crown and GitHub suggests LLM-oriented development played a role. Taking JavaScript and TypeScript together, however, places our ecosystem far out in front.

Solving New York Times Pips Puzzle -

Pips is The New York Times' daily puzzle where you have to place dominos onto a board within a set of region restrictions. It’s an interesting puzzle to consider how to solve algorithmically.

👩‍💻CODE SHOT

What do you think the following code does?

function checkio(t: string) {
    let r = []
    let m = -1
    for (let i = 0, j = 0; 1; i = j) {
        while(+t.slice(i,++j) <= m)
            if (j > t.length)
                return r
        m = +t.slice(i,j)
        r.push(m)
    }
}

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