createUser(user, true, false) works. It's also surprisingly hard to read. Here's why I've stopped writing APIs like this in JavaScript.

Matt Smith

Boolean arguments like `createUser(user, true, false)` are a common readability problem in JavaScript APIs. When call sites use multiple positional booleans, readers must jump to the function definition to understand what each value means. The recommended fix is replacing positional booleans with named options objects (e.g., `{ isAdmin: true, sendWelcomeEmail: false }`), which makes call sites self-documenting. In some cases, a boolean flag signals two distinct actions that deserve separate functions entirely. TypeScript type-checking doesn't solve this problem since the issue is semantic clarity, not type correctness.

I keep tripping over

I’m not reading code anymore, I’m decoding it

Sometimes the boolean is hiding a different action

<p>In the old days, when the IDEs were lacking features that are common today, I would say this was a bigger issue.</p>
<p>Now we can just hover our mouse pointer over the function name and get its signature, see the parameters names and their description also (if well documented, of course).</p>
