Results for “form”

A form's state as a pure reducer: values, touched fields, validator errors and the submit, for useReducer.

Wire a label, hint and error message to one form control by id, the accessible way (GOV.UK form group pattern).

An optional stylesheet for the react.form elements' caps-* classes, themed by --caps-form-* custom properties.

One checkbox with its label beside it, such as "I agree to the terms" (GOV.UK single checkbox).

A form button in primary, secondary or warning style that stays focusable while loading (GOV.UK button).

Group related inputs under a legend, with a hint and error message described to the whole group (GOV.UK fieldset).

Choose exactly one of several radios, with item hints, an "or" divider and inline yes/no (GOV.UK radios).

A password input with a Show/Hide button and an optional live checklist of a password policy (GOV.UK password input).

A labelled drop-down list with a hint, error message and an optional empty first option (GOV.UK select).

A question answered by ticking any of several checkboxes, with item hints and an exclusive "None" (GOV.UK checkboxes).

A labelled single-line text input with hint, error message, autocomplete, prefix and suffix (GOV.UK text input).

Day, month and year boxes under one legend, with hint, error message and the boxes in error marked (GOV.UK date input).

A "There is a problem" box linking to each field in error, focused on arrival, built from a validator's fields (GOV.UK).

The GOV.UK character count message for a text box: characters or words left or over a limit, with a threshold.

Check a date typed into day, month and year boxes, with GOV.UK's error messages and the boxes to mark in error.

A labelled multi-line text box with hint, error and an optional live character or word count (GOV.UK).

Check a login form (email, password): the normalised email to look up, or a message for each field to fix.

Check a change-password form: current password given and correct, new one meeting the policy and different.

Validate a sign-up form (email, password, name) in one call, with a message per field, in the browser and the API alike.

The to-do item type (Todo, TodoDraft, Recurrence) and its validators, with a message per field.

Read a Repeat box, "every 2 weeks" or "every monday on 2026-10-05", as a todo's recurrence, or null.

Read a tags box as typed, "#Home, work errands", into normalised tags: split on spaces and commas.

Parse IPv6 addresses and write them in RFC 5952 canonical form: lower-case, zeros compressed, IPv4 embedded.

Parse, format and check dotted-quad IPv4 addresses, refusing leading zeros, octal, hex and short forms.

Validate a MAC address in colon, hyphen, Cisco dot or bare form and normalise it, with multicast and local bits.

Check an ISBN-10 or ISBN-13 and convert between them; the normalised form is always the ISBN-13.

Clean up tags as typed: trim, drop the #, lower-case slug form, drop empties and duplicates, keep the order.

Check a double-entry journal: debits equal credits, no zero or two-sided lines, one currency, well-formed account codes.

The token from an HTTP Authorization header of the form "Bearer <token>" (RFC 6750), or null if it has none.

Check an EAN-8, UPC-A, EAN-13 or GTIN-14 barcode number against the GS1 mod-10 check digit.

The UK personal tax year containing a date: 6 April to 5 April, with HMRC's label.

Text to UTF-8 bytes and strictly back (RFC 3629), so hashing and signing see the same bytes in every language.

Cost half-hourly consumption against time-of-use rates: Economy 7 windows or Agile-style half-hourly prices.

Seconds to wait from an HTTP Retry-After header (delay-seconds or an HTTP date), or null if missing or malformed.

Tidy a personal name: trim, collapse whitespace and title-case, with Mc, Mac, O', hyphen and van/de rules.

Parse durations written as 1h30m, 90m or 01:30, add them up in whole minutes, and format the total.

Check the format of a SWIFT/BIC code (8 or 11 characters) and split it into its parts.

Check the format of a commodity code: 6-digit HS, 8-digit CN or 10-digit TARIC/UK code, with chapter and heading checks.

Exact integer arithmetic of any size, on decimal strings, for powers and products that overflow 64 bits.

Validate one network inventory entry: name, host, ports, optional MAC and subnet, with every problem listed.

Spell out a whole number in British English words, with "and" the way a cheque writes it.

Trim an email address and lower-case its domain for storage and lookup, or null if it is not a plausible address.

Normalise a phone number to E.164 (+447700900123) using a default country's trunk and dialling prefixes.

Check a new password against a named policy (NIST SP 800-63B-4 by default): length, common passwords, name and email.

Check a host name against RFC 1123 and RFC 952 label rules and length limits, and normalise it.

The to-do list reducer: add, edit, complete, remove, clear and reorder todos, each returning a new list.

Statutory interest on a judgment debt (8% simple, daily) or a late commercial debt, England and Wales.

Fuzzy-match a name against existing clients and parties for a conflict check: normalised, token-sorted Jaro-Winkler.

Check an NHS number's modulus 11 check digit and normalise it to ten digits.

Bytes to base64 and base64url text and back (RFC 4648), with strict decoding, identically in every language.

Bytes to lowercase hexadecimal text and back (RFC 4648 base16), strictly, identically in every language.

CIDR blocks: network, broadcast, first and last host, host count, netmask and prefix, and membership.

Read a typed due date like "tomorrow", "next friday", "in 2 weeks" or "2026-10-01" as a date, relative to today.

Check a UK VAT registration number against HMRC's mod-97 checksum, including the post-2010 9755 variant.

Divide two integers of any size with an explicit rounding mode, on decimal strings, for exact money sums past 2^53.

ISO 8601 week number and week-numbering year of a date: weeks start Monday, week 1 holds the first Thursday.

Check a digit string against the Luhn mod-10 checksum used by payment cards and many identifiers.

Check a UK National Insurance number's format and HMRC's disallowed prefix letters, and normalise it.

Display an NHS number in the 3-3-4 format ("943 476 5919") after checking its modulus 11 check digit.

Concrete for slabs, strip footings, pads and round columns: volume to the litre and an order rounded up to 0.1 m³.

Ofgem energy price cap unit rate and daily standing charge for a fuel and payment method on a date (GB average).

Validate a UK postcode and normalise it to canonical upper case with one space before the inward code.

Check a Companies House company number's format and prefix (SC, NI, OC, LP...) and zero-pad it to eight characters.

Check an HMRC Unique Taxpayer Reference's modulus 11 check digit, accepting the K and spacing people type.

Hex colours to RGB and back, and sRGB channels to linear light and back, identically in every language.

Fertiliser product rate (kg/ha and total) to meet N, P2O5 and K2O targets from its analysis, limiting nutrient first.

Field area in square metres, hectares and acres from a boundary polygon of latitude/longitude points.

Issue an API's HS256 access token, read one from an Authorization header, and refuse revoked or superseded ones.

Reduce a long series to a few points that keep its visual shape, by Largest-Triangle-Three-Buckets (LTTB).

The colour at a point along a sequential or diverging ramp, mixed in OKLab so steps look even; hex in, hex out.

Convert a rate between percent, basis points and a plain ratio exactly, as decimal text or integer basis points.

Classify an IPv4 or IPv6 address as loopback, private, link-local, multicast, documentation, CGNAT or global.

An RFC 3339 timestamp with a Z or offset, such as 2026-09-26T13:00:00+01:00, to Unix time in whole seconds.

Is this a plausible email address? A documented, pragmatic subset of RFC 5322, not the full grammar.

Check an IBAN against the ISO 13616 mod-97-10 checksum and the registered length for its country.

Check a 20-character Legal Entity Identifier against its ISO 17442 / ISO 7064 MOD 97-10 check digits.

Allow a login attempt or lock the account out, from its recent failed attempts, with the seconds until it may retry.

UK bank and public holidays for a region and year, as published by gov.uk, including one-off holidays.

Weighted percentage across coursework and exam components, exact as a fraction, then rounded once.

Compute or check the GS1 mod-10 check digit of any GS1 key: GTIN, SSCC, GLN, GSRN, GDTI, GSIN and the rest.

Working days between two dates, excluding weekends and a caller-supplied holiday list.

When a repeating todo's due date is moved by hand, move its series with it: the new date becomes the anchor.

Scale a recipe to a new number of portions, tidying metric units (g to kg, mL to L) and rounding to kitchen precision.

Customer lifetime value, LTV to CAC ratio and CAC payback months from ARPA, gross margin, churn and CAC.

Hash a password for storage as pbkdf2_sha256$iterations$salt$hash, verify one in constant time, and spot weak hashes.

Shorten text to a maximum length on a word boundary and add an ellipsis, counting Unicode code points.

Turn one typed line like "Pay rent tomorrow !high #home every month" into a todo draft.

PAYE income tax for one pay period from a tax code, cumulative or week 1/month 1, by HMRC's tax table routines.

UK nine-box VAT return totals for a period from categorised sales and purchases (VAT Notice 700/12).

US sales tax on a sale: the state's base rate from dated data plus a local rate the caller supplies.

Time-weighted return from valuations taken at each external cash flow, geometrically linked exactly.

Check a QRISK3 cardiovascular risk input set against the calculator's published ranges; does not compute risk.

Employer match on a donation: a ratio in basis points, limited by a per-donor cap and a programme budget.

Retention held and released on a construction valuation: full rate, half at practical completion, none at the end.

Roof pitch in degrees, rafter length and roof slope area from span, rise and length.

Explode a multi-level bill of materials into exact total quantities per component, with scrap and cycle checks.

Tuition fee instalment schedule from a total, shares and due dates, exact to the penny.

Rolled-up standard cost of one unit of a product from its BOM, bought-in costs, and labour and overhead rates.

How many identical cartons fit in a 20ft, 40ft or 40ft high-cube container or a 13.6 m trailer, by space and by weight.

Whole units to start for a required good output at a process yield, and the scrap that allows for.