Show HN: GolemUI – Declarative Form Engine

import { useForm, useWatch } from 'react-hook-form' ; type FormData = { email : string ; password : string ; accountType : 'Free' | 'Pro' | 'Enterprise' ; companyName ?: string ; seats ?: number ; subscribe : boolean ; frequency ?: string ; terms : boolean ; }; export function SignupForm () { const { register , control , handleSubmit , formState : { errors } } = useForm < FormData >({ defaultValues: { accountType: 'Free' , subscribe: false , terms: false }, }); const accountType = useWatch ({ control, name: 'accountType' }); const subscribe = useWatch ({ control, name: 'subscribe' }); return ( < form onSubmit = { handleSubmit (( data ) => console. log (data))}> < label >Email < input type = "email" { ... register ( 'email' , { required: true , pattern: / ^ [ ^ \s@] + @ [ ^ \s@] + \. [ ^ \s@] +$ / , })} /> {errors.email && < span >Valid email required</ span >} </ label > < label >Password < input type = "password" { ... register ( 'password' , { required: true , minLength: 8 , })} /> {errors.password && < span >Min 8 characters</ span >} </ label > < label >Account type < select { ... register ( 'accountType' , { required: true })}> < option >Free</ option > < option >Pro</ option > < option >Enterprise</ option > </ select > </ label > {accountType !== 'Free' && ( < label >Company name < input { ... register ( 'companyName' , { required: true })} /> {errors.companyName && < span >Required</ span >} </ label > )} {accountType === 'Enterprise' && ( < label >Seats < input type = "number" { ... register ( 'seats' , { required: true , min: 5 , max: 1000 , valueAsNumber: true , })} /> {errors.seats && < span >Between 5 and 1000</ span >} </ label > )} < label > < input type = "checkbox" { ... register ( 'subscribe' )} /> Subscribe to product updates </ label > {subscribe && ( < label >Frequency < select { ... register ( 'frequency' , { required: true })}> < option >Daily</ option > < option >Weekly</ option > < option >Monthly</ option > </ select > </ label > )} < label > < input type = "checkbox" { ... register ( 'terms' , { validate : ( v ) => v === true || 'Required' , })} /> I accept the terms of service </ label > < button type = "submit" >Sign up</ button > </ form > ); }

import { Component, signal } from '@angular/core' ; import { form, Control, schema, required, email, minLength, validate, } from '@angular/forms/signals' ; interface Signup { email : string ; password : string ; accountType : 'Free' | 'Pro' | 'Enterprise' ; companyName : string ; seats : number | null ; subscribe : boolean ; frequency : 'Daily' | 'Weekly' | 'Monthly' ; terms : boolean ; } const signupSchema = schema < Signup >(( data ) => { required (data.email); email (data.email); required (data.password); minLength (data.password, 8 ); validate (data.companyName, ({ value , valueOf }) => valueOf (data.accountType) !== 'Free' && ! value () ? { kind: 'required' } : null ); validate (data.seats, ({ value , valueOf }) => { if ( valueOf (data.accountType) !== 'Enterprise' ) return null ; const v = value (); return v != null && v >= 5 && v <= 1000 ? null : { kind: 'seats' }; }); validate (data.terms, ({ value }) => value () ? null : { kind: 'mustAccept' }); }); @ Component ({ selector: 'app-signup' , imports: [Control], template: ` <form (submit)="onSubmit($event)"> <label>Email <input [control]="f.email" type="email" /> </label> <label>Password <input [control]="f.password" type="password" /> </label> <label>Account type <select [control]="f.accountType"> <option>Free</option> <option>Pro</option> <option>Enterprise</option> </select> </label> @if (data().accountType !== 'Free') { <label>Company name <input [control]="f.companyName" /> </label> } @if (data().accountType === 'Enterprise') { <label>Seats <input [control]="f.seats" type="number" min="5" max="1000" /> </label> } <label> <input [control]="f.subscribe" type="checkbox" /> Subscribe to product updates </label> @if (data().subscribe) { <label>Frequency <select [control]="f.frequency"> <option>Daily</option> <option>Weekly</option> <option>Monthly</option> </select> </label> } <label> <input [control]="f.terms" type="checkbox" /> I accept the terms of service </label> <button type="submit" [disabled]="!f().valid()">Sign up</button> </form> ` , }) export class SignupForm { data = signal < Signup >({ email: '' , password: '' , accountType: 'Free' , companyName: '' , seats: null , subscribe: false , frequency: 'Daily' , terms: false , }); f = form ( this .data, signupSchema); onSubmit ( e : Event ) { e. preventDefault (); if ( this . f (). valid ()) console. log ( this . data ()); } }

import { LitElement, html } from 'lit' ; import { customElement, state } from 'lit/decorators.js' ; type Account = 'Free' | 'Pro' | 'Enterprise' ; @ customElement ( 'signup-form' ) export class SignupForm extends LitElement { @ state () email = '' ; @ state () password = '' ; @ state () accountType : Account = 'Free' ; @ state () companyName = '' ; @ state () seats : number | null = null ; @ state () subscribe = false ; @ state () frequency = 'Daily' ; @ state () terms = false ; @ state () errors : Record < string , string > = {}; private bind = ( key : keyof this ) => ( e : Event ) => { const t = e.target as HTMLInputElement ; ( this as any )[key] = t.type === 'checkbox' ? t.checked : t.value; }; private validate () { const e : Record < string , string > = {}; if ( ! / ^ [ ^ \s@] + @ [ ^ \s@] + \. [ ^ \s@] +$ / . test ( this .email)) e.email = 'Valid email' ; if ( this .password. length < 8 ) e.password = 'Min 8 characters' ; if ( this .accountType !== 'Free' && ! this .companyName) e.companyName = 'Required' ; if ( this .accountType === 'Enterprise' ) { const s = this .seats; if (s == null || s < 5 || s > 1000 ) e.seats = 'Between 5 and 1000' ; } if ( this .subscribe && ! this .frequency) e.frequency = 'Required' ; if ( ! this .terms) e.terms = 'Required' ; return e; } private onSubmit ( ev : Event ) { ev. preventDefault (); this .errors = this . validate (); if ( ! Object. keys ( this .errors). length ) console. log ( this ); } render () { return html ` <form @submit=${ this . onSubmit }> <label>Email <input type="email" .value=${ this . email } @input=${ this . bind ( 'email' ) } /> ${ this . errors . email ? html `<span>${ this . errors . email }</span>` : null } </label> <label>Password <input type="password" .value=${ this . password } @input=${ this . bind ( 'password' ) } /> ${ this . errors . password ? html `<span>${ this . errors . password }</span>` : null } </label> <label>Account type <select .value=${ this . accountType } @change=${ this . bind ( 'accountType' ) }> <option>Free</option><option>Pro</option><option>Enterprise</option> </select> </label> ${ this . accountType !== 'Free' ? html ` <label>Company name <input .value=${ this . companyName } @input=${ this . bind ( 'companyName' ) } /> </label>` : null } ${ this . accountType === 'Enterprise' ? html ` <label>Seats <input type="number" .value=${ this . seats ?? ''} @input=${ this . bind ( 'seats' ) } /> </label>` : null } <label> <input type="checkbox" .checked=${ this . subscribe } @change=${ this . bind ( 'subscribe' ) } /> Subscribe to product updates </label> ${ this . subscribe ? html ` <label>Frequency <select .value=${ this . frequency } @change=${ this . bind ( 'frequency' ) }> <option>Daily</option><option>Weekly</option><option>Monthly</option> </select> </label>` : null } <label> <input type="checkbox" .checked=${ this . terms } @change=${ this . bind ( 'terms' ) } /> I accept the terms of service </label> <button type="submit">Sign up</button> </form> ` ; } }

< script setup lang = "ts" > import { useForm, useField } from 'vee-validate' ; import * as yup from 'yup' ; type Account = 'Free' | 'Pro' | 'Enterprise' ; const schema = yup. object ({ email: yup. string (). email (). required (), password: yup. string (). min ( 8 ). required (), accountType: yup. mixed < Account >(). oneOf ([ 'Free' , 'Pro' , 'Enterprise' ]). required (), companyName: yup. string (). when ( 'accountType' , { is : ( t : Account ) => t !== 'Free' , then : ( s ) => s. required (), }), seats: yup. number (). when ( 'accountType' , { is: 'Enterprise' , then : ( s ) => s. required (). min ( 5 ). max ( 1000 ), }), subscribe: yup. boolean (), frequency: yup. string (). when ( 'subscribe' , { is: true , then : ( s ) => s. required (), }), terms: yup. boolean (). oneOf ([ true ], 'Required' ), }); const { handleSubmit , errors } = useForm ({ validationSchema: schema, initialValues: { accountType: 'Free' , subscribe: false , terms: false }, }); const { value : email } = useField < string >( 'email' ); const { value : password } = useField < string >( 'password' ); const { value : accountType } = useField < Account >( 'accountType' ); const { value : companyName } = useField < string >( 'companyName' ); const { value : seats } = useField < number | null >( 'seats' ); const { value : subscribe } = useField < boolean >( 'subscribe' ); const { value : frequency } = useField < string >( 'frequency' ); const { value : terms } = useField < boolean >( 'terms' ); const onSubmit = handleSubmit (( vals ) => console. log (vals)); </ script > < template > < form @ submit = " onSubmit " > < label >Email < input v-model = " email " type = "email" /> < span v-if = " errors.email " >{{ errors.email }}</ span > </ label > < label >Password < input v-model = " password " type = "password" /> < span v-if = " errors.password " >{{ errors.password }}</ span > </ label > < label >Account type < select v-model = " accountType " > < option >Free</ option >< option >Pro</ option >< option >Enterprise</ option > </ select > </ label > < label v-if = " accountType !== 'Free'" >Company name < input v-model = " companyName " /> < span v-if = " errors.companyName " >{{ errors.companyName }}</ span > </ label > < label v-if = " accountType === 'Enterprise'" >Seats < input v-model . number = " seats " type = "number" min = "5" max = "1000" /> < span v-if = " errors.seats " >{{ errors.seats }}</ span > </ label > < label > < input v-model = " subscribe " type = "checkbox" /> Subscribe to product updates </ label > < label v-if = " subscribe " >Frequency < select v-model = " frequency " > < option >Daily</ option >< option >Weekly</ option >< option >Monthly</ option > </ select > </ label > < label > < input v-model = " terms " type = "checkbox" /> I accept the terms of service </ label > < button type = "submit" >Sign up</ button > </ form > </ template >

< form id = "signup" > < label >Email < input name = "email" type = "email" required /> </ label > < label >Password < input name = "password" type = "password" required minlength = "8" /> </ label > < label >Account type < select name = "accountType" required > < option >Free</ option >< option >Pro</ option >< option >Enterprise</ option > </ select > </ label > < label data-show = "companyName" hidden >Company name < input name = "companyName" /> </ label > < label data-show = "seats" hidden >Seats < input name = "seats" type = "number" min = "5" max = "1000" /> </ label > < label > < input name = "subscribe" type = "checkbox" /> Subscribe to product updates </ label > < label data-show = "frequency" hidden >Frequency < select name = "frequency" > < option >Daily</ option >< option >Weekly</ option >< option >Monthly</ option > </ select > </ label > < label > < input name = "terms" type = "checkbox" /> I accept the terms of service </ label > < button type = "submit" >Sign up</ button > </ form > < script > const f = document. querySelector ( '#signup' ); const show = ( key , on , req ) => { const el = f. querySelector ( `[data-show="${ key }"]` ); el.hidden = ! on; f.elements[key].required = on && req; }; function sync () { const t = f.accountType.value; show ( 'companyName' , t !== 'Free' , true ); show ( 'seats' , t === 'Enterprise' , true ); show ( 'frequency' , f.subscribe.checked, true ); } f.accountType. addEventListener ( 'change' , sync); f.subscribe. addEventListener ( 'change' , sync); sync (); f. addEventListener ( 'submit' , ( e ) => { e. preventDefault (); if ( ! f.terms.checked) { f.terms. setCustomValidity ( 'Required' ); } else { f.terms. setCustomValidity ( '' ); } if ( ! f. checkValidity ()) return f. reportValidity (); console. log (Object. fromEntries ( new FormData (f))); }); </ script >

import { gui } from '@golemui/gui-shared' ; import { GuiForm } from '@golemui/gui-react' ; const signupForm = [ gui.inputs. textInput ( 'email' , { label: 'Email' , validator: { required: true , format: 'email' }, }), gui.inputs. password ( 'password' , { label: 'Password' , validator: { required: true , minLength: 8 }, }), gui.inputs. dropdown ( 'accountType' , { label: 'Account type' , items: [ 'Free' , 'Pro' , 'Enterprise' ], defaultValue: 'Free' , validator: { type: 'string' , required: true }, }), gui.inputs. textInput ( 'companyName' , { label: 'Company name' , validator: { required: true }, include: { when: '$form.accountType !== "Free"' }, }), gui.inputs. numberInput ( 'seats' , { label: 'Seats' , validator: { required: true , minimum: 5 , maximum: 1000 }, include: { when: '$form.accountType === "Enterprise"' }, }), gui.inputs. checkbox ( 'subscribe' , { label: 'Subscribe to product updates' , }), gui.inputs. dropdown ( 'frequency' , { label: 'Frequency' , items: [ 'Daily' , 'Weekly' , 'Monthly' ], validator: { type: 'string' , required: true }, include: { when: '$form.subscribe === true' }, }), gui.inputs. checkbox ( 'terms' , { label: 'I accept the terms of service' , validator: { const: true }, }), gui.actions. button ({ label: 'Sign up' , actionType: 'submit' }), ]; export function SignupForm () { return ( < GuiForm config = {{ formDef: signupForm }} formSubmit = {( data ) => console. log (data)} /> ); }

import { Component } from '@angular/core' ; import { CommonModule } from '@angular/common' ; import { gui } from '@golemui/gui-shared' ; import { FormComponent } from '@golemui/gui-angular' ; const signupForm = [ gui.inputs. textInput ( 'email' , { label: 'Email' , validator: { required: true , format: 'email' }, }), gui.inputs. password ( 'password' , { label: 'Password' , validator: { required: true , minLength: 8 }, }), gui.inputs. dropdown ( 'accountType' , { label: 'Account type' , items: [ 'Free' , 'Pro' , 'Enterprise' ], defaultValue: 'Free' , validator: { type: 'string' , required: true }, }), gui.inputs. textInput ( 'companyName' , { label: 'Company name' , validator: { required: true }, include: { when: '$form.accountType !== "Free"' }, }), gui.inputs. numberInput ( 'seats' , { label: 'Seats' , validator: { required: true , minimum: 5 , maximum: 1000 }, include: { when: '$form.accountType === "Enterprise"' }, }), gui.inputs. checkbox ( 'subscribe' , { label: 'Subscribe to product updates' , }), gui.inputs. dropdown ( 'frequency' , { label: 'Frequency' , items: [ 'Daily' , 'Weekly' , 'Monthly' ], validator: { type: 'string' , required: true }, include: { when: '$form.subscribe === true' }, }), gui.inputs. checkbox ( 'terms' , { label: 'I accept the terms of service' , validator: { const: true }, }), gui.actions. button ({ label: 'Sign up' , actionType: 'submit' }), ]; @ Component ({ selector: 'app-signup' , imports: [CommonModule, FormComponent], template: `<gui-form [config]="config" (formSubmit)="onSubmit($event)"></gui-form>` , }) export class SignupForm { protected config = { formDef: signupForm }; onSubmit ( data : unknown ) { console. log (data); } }

import { LitElement, html } from 'lit' ; import { customElement } from 'lit/decorators.js' ; import { gui } from '@golemui/gui-shared' ; import '@golemui/gui-lit' ; const signupForm = [ gui.inputs. textInput ( 'email' , { label: 'Email' , validator: { required: true , format: 'email' }, }), gui.inputs. password ( 'password' , { label: 'Password' , validator: { required: true , minLength: 8 }, }), gui.inputs. dropdown ( 'accountType' , { label: 'Account type' , items: [ 'Free' , 'Pro' , 'Enterprise' ], defaultValue: 'Free' , validator: { type: 'string' , required: true }, }), gui.inputs. textInput ( 'companyName' , { label: 'Company name' , validator: { required: true }, include: { when: '$form.accountType !== "Free"' }, }), gui.inputs. numberInput ( 'seats' , { label: 'Seats' , validator: { required: true , minimum: 5 , maximum: 1000 }, include: { when: '$form.accountType === "Enterprise"' }, }), gui.inputs. checkbox ( 'subscribe' , { label: 'Subscribe to product updates' , }), gui.inputs. dropdown ( 'frequency' , { label: 'Frequency' , items: [ 'Daily' , 'Weekly' , 'Monthly' ], validator: { type: 'string' , required: true }, include: { when: '$form.subscribe === true' }, }), gui.inputs. checkbox ( 'terms' , { label: 'I accept the terms of service' , validator: { const: true }, }), gui.actions. button ({ label: 'Sign up' , actionType: 'submit' }), ]; @ customElement ( 'signup-form' ) export class SignupForm extends LitElement { private config = { formDef: signupForm }; override createRenderRoot () { return this ; } render () { return html ` <gui-form .config=${ this . config } @formSubmit=${ ( e : CustomEvent ) => console . log ( e . detail ) } ></gui-form> ` ; } }

< script setup lang = "ts" > import { gui } from '@golemui/gui-shared' ; import { GuiForm } from '@golemui/gui-vue' ; const signupForm = [ gui.inputs. textInput ( 'email' , { label: 'Email' , validator: { required: true , format: 'email' }, }), gui.inputs. password ( 'password' , { label: 'Password' , validator: { required: true , minLength: 8 }, }), gui.inputs. dropdown ( 'accountType' , { label: 'Account type' , items: [ 'Free' , 'Pro' , 'Enterprise' ], defaultValue: 'Free' , validator: { type: 'string' , required: true }, }), gui.inputs. textInput ( 'companyName' , { label: 'Company name' , validator: { required: true }, include: { when: '$form.accountType !== "Free"' }, }), gui.inputs. numberInput ( 'seats' , { label: 'Seats' , validator: { required: true , minimum: 5 , maximum: 1000 }, include: { when: '$form.accountType === "Enterprise"' }, }), gui.inputs. checkbox ( 'subscribe' , { label: 'Subscribe to product updates' , }), gui.inputs. dropdown ( 'frequency' , { label: 'Frequency' , items: [ 'Daily' , 'Weekly' , 'Monthly' ], validator: { type: 'string' , required: true }, include: { when: '$form.subscribe === true' }, }), gui.inputs. checkbox ( 'terms' , { label: 'I accept the terms of service' , validator: { const: true }, }), gui.actions. button ({ label: 'Sign up' , actionType: 'submit' }), ]; const config = { formDef: signupForm }; const onSubmit = ( data : unknown ) => console. log (data); </ script > < template > < GuiForm : config = " config " @ form-submit = " onSubmit " /> </ template >