Fingers hovering over npm install, I paused. Another library? Nah.
This dev did too. Leading a TS-heavy project, feeling like a fraud amid the angle brackets. Solution? Whip up form-validator-ts from nothing. Tiny. Type-safe. Brutally honest about your bad inputs.
You feed it a schema, some dodgy data. Boom—errors with types intact. Here’s the money shot:
const result = validate( { email: { required: true, pattern: /\S+@\S+.\S+/ }, password: { required: true, minLength: 8 }, }, { email: “notanemail”, password: “abc”, } ) // { valid: false, errors: { email: [“Must be a valid email”], password: [“Minimum length is 8”] } }
Clean. No bloat. Published to npm. Two hours of head-scratching, zero weeks of YouTube.
Why Build a TypeScript Form Validator from Scratch?
Look. TypeScript’s everywhere now—React apps, Node backends, your grandma’s grocery list validator (okay, exaggeration). But devs paste generics like copy-paste parrots. Don’t grok ‘em. Just… works?
This guy’s fix? Force the issue. No Zod. No Yup. Raw TS. Schema as object. Validators per field: required, minLength, pattern. Infer types from schema—boom, autocomplete magic without the mystery.
And here’s my twist, absent from the original: It’s TS’s ’70s BASIC moment. Back when coders typed PRINT “HELLO” to feel the machine hum. Tutorials? Theory. Building? Blood, sweat, pixels. Predict this: In five years, TS bootcamps will mandate library-free sprints. Muscle memory over manpages.
Skeptical? Fair. Corporate hype loves “type safety” as buzz. But this? No spin. Just a dev admitting, “I felt lost.” Refreshing.
Short version: It works. Plug in, validate. Errors typed. Done.
Is form-validator-ts Better Than the Big Boys?
Zod’s king. Yup’s veteran. Why this upstart? Size—micro. Learning curve? Yours to own. No “parse” rituals or schema DSLs to memorize.
Tested it. npm install form-validator-ts. Quick script:
import { validate } from 'form-validator-ts';
const schema = {
name: { required: true, minLength: 2 },
age: { required: true, type: 'number', min: 18 }
};
const data = { name: 'A', age: 'seventeen' };
console.log(validate(schema, data));
// { valid: false, errors: { name: ["Minimum length is 2"], age: ["Must be a number", "Minimum value is 18"] } }
Handles strings, numbers, patterns, arrays even (basics). Custom validators? Hook ‘em in. Not exhaustive—misses nested objects, say—but for forms? Gold.
Dry humor alert: If Zod’s a Swiss Army knife, this is the pocket blade. Sharp enough for most guts.
But wait—types. Schema infers data shape perfectly. SignupForm above? IntelliSense knows email’s string, password too. No lies.
Critique time. Original skips edge cases: locales? Async checks? Nah. Fine for toy. Real project? Layer on.
What Makes TypeScript Click—Finally?
Honestly the TypeScript stuff was less confusing than I expected once I stopped trying to understand it abstractly and just wrote it.
Nailed it. Tutorials drone: “Generics constrain types!” Eyes glaze. Build? Errors scream: “Type ‘string’ is not assignable to ‘number’.” Fix. Repeat. Ah—gotcha.
I’ve seen it. JS vets stumble on TS. Mapped types? Conditional? Abstract hell. This validator? Hits mapped types (schema to errors), conditionals (if required && empty), unions (error arrays).
Unique angle: Parallels jQuery era. Everyone grabbed libs pre-ES6. Post? Vanilla JS renaissance. TS needs that. Ditch crates, forge swords.
Two hours confusion > two weeks vids. Amen.
Pro tip: Fork it. Add nested validation. Deploy. Resume fodder.
Why Does This Matter for Frontend Devs?
Forms suck. Always. Spam, typos, rage quits. TS nails ‘em early—compile-time wins.
Libs bloat bundles. This? 2KB gzipped (guessing—tiny). Perf pedants rejoice.
Bigger: TS adoption stalls at “kinda works.” Hands-on like this? Converts skeptics. Your team? Less “WTF is this error?”
Prediction: npm downloads spike. Clones sprout. TS ecosystem toughens.
Or not. World keeps Zodding. But hey—choice.
Single sentence warning: Don’t ship production sans tests. Obvious?
Deep dive: Internals. validate generic. Schema keys become error keys. Recursive-ish per field. Patterns compile-checked. Smart.
Messy? Schema’s loose—any validators? Flexible, error-prone. Tradeoff.
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Frequently Asked Questions
What is form-validator-ts?
A tiny npm package for type-safe form validation in TypeScript, built without dependencies. Pass schema and data, get typed errors back.
Should I use form-validator-ts instead of Zod?
For learning TS or micro-apps, yes. Production heavy-lifting? Stick to Zod—it’s battle-tested.
Is building a TypeScript form validator from scratch worth it?
Absolutely, if you’re stuck on TS concepts. Beats tutorials; builds real intuition fast.
