Glossary — Z
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Zero-config
A property of tools that work out of the box with no setup. Next.js advertises being zero-config — drop in pages, run npm run dev, and you have routing, dev server, and bundling. (You can always add configuration when you need it; the point is you don’t have to.)
See also: Next.js
z-index (CSS)
The CSS property that controls which element appears on top when elements overlap. Higher number = on top. Only applies to positioned elements (position: relative/absolute/fixed/sticky). Famously a source of “why is this modal hidden behind the navbar” problems — once a project has competing z-indexes, you end up with values like z-index: 9999999.
See also: CSS
Zod
A popular TypeScript-first schema validation library. Define a schema once; get both runtime validation AND a TypeScript type. Excellent for validating data crossing trust boundaries (API inputs, environment variables, form submissions).
import { z } from "zod";
const User = z.object({ name: z.string(), age: z.number() });
const parsed = User.parse(input); // throws if invalid; parsed is fully typedSee also: TypeScript, Schema