react.form.radio-group React ^19 · TypeScript only
Choose exactly one of several radios, with item hints, an "or" divider and inline yes/no (GOV.UK radios).
Not available in Python
1.0.1
ts
14 tests
react.form.button React ^19 · TypeScript only
A form button in primary, secondary or warning style that stays focusable while loading (GOV.UK button).
Not available in Python
1.0.1
ts
13 tests
react.form.select React ^19 · TypeScript only
A labelled drop-down list with a hint, error message and an optional empty first option (GOV.UK select).
Not available in Python
1.0.1
ts
15 tests
react.form.checkbox React ^19 · TypeScript only
One checkbox with its label beside it, such as "I agree to the terms" (GOV.UK single checkbox).
Not available in Python
1.0.1
ts
14 tests
react.form.text-field React ^19 · TypeScript only
A labelled single-line text input with hint, error message, autocomplete, prefix and suffix (GOV.UK text input).
Not available in Python
1.0.1
ts
14 tests
react.form.textarea React ^19 · TypeScript only
A labelled multi-line text box with hint, error and an optional live character or word count (GOV.UK).
Not available in Python
1.0.1
ts
16 tests
react.form.checkbox-group React ^19 · TypeScript only
A question answered by ticking any of several checkboxes, with item hints and an exclusive "None" (GOV.UK checkboxes).
Not available in Python
1.0.1
ts
24 tests
react.form.fieldset React ^19 · TypeScript only
Group related inputs under a legend, with a hint and error message described to the whole group (GOV.UK fieldset).
Not available in Python
1.0.1
ts
10 tests
react.form.date-input React ^19 · TypeScript only
Day, month and year boxes under one legend, with hint, error message and the boxes in error marked (GOV.UK date input).
Not available in Python
1.0.1
ts
14 tests
react.form.error-summary React ^19 · TypeScript only
A "There is a problem" box linking to each field in error, focused on arrival, built from a validator's fields (GOV.UK).
Not available in Python
1.0.1
ts
21 tests
react.form.styles React ^19 · TypeScript only
An optional stylesheet for the react.form elements' caps-* classes, themed by --caps-form-* custom properties.
Not available in Python
1.0.1
ts
21 tests
react.form.form-field React ^19 · TypeScript only
Wire a label, hint and error message to one form control by id, the accessible way (GOV.UK form group pattern).
Not available in Python
1.0.1
ts
19 tests
react.form.password-field React ^19 · TypeScript only
A password input with a Show/Hide button and an optional live checklist of a password policy (GOV.UK password input).
Not available in Python
1.0.1
ts
22 tests
form.state TypeScript only
A form's state as a pure reducer: values, touched fields, validator errors and the submit, for useReducer.
Not available in Python
1.0.1
ts
40 tests
form.character-count
The GOV.UK character count message for a text box: characters or words left or over a limit, with a threshold.
character_count in Python
1.0.1
py rs ts
32 tests
form.date-parts
Check a date typed into day, month and year boxes, with GOV.UK's error messages and the boxes to mark in error.
validate_date_parts in Python
1.0.1
py rs ts
49 tests
charts.interpolate-color
The colour at a point along a sequential or diverging ramp, mixed in OKLab so steps look even; hex in, hex out.
interpolate_color in Python
1.0.0
py rs ts
19 tests
todo.reschedule-recurrence
When a repeating todo's due date is moved by hand, move its series with it: the new date becomes the anchor.
reschedule_recurrence in Python
1.0.0
py rs ts
14 tests
todo.list
The to-do list reducer: add, edit, complete, remove, clear and reorder todos, each returning a new list.
A group of 8: add_todo, update_todo, toggle_todo, remove_todo, clear_completed, toggle_all, move_todo, toggle_all_mode
1.1.0
py rs ts
102 tests
math.exp
e to the power x from + - * / only, so TypeScript, Python and Rust return the same double for the same input.
exp in Python
1.0.1
py rs ts
10 tests
monitor.alert-state
Step an alert through inactive, pending, firing and resolved, and say which notification to send.
next_alert_state in Python
1.0.0
py rs ts
25 tests
todo.parse-repeat
Read a Repeat box, "every 2 weeks" or "every monday on 2026-10-05", as a todo's recurrence, or null.
parse_repeat in Python
1.0.0
py rs ts
22 tests
todo.parse-quick-add
Turn one typed line like "Pay rent tomorrow !high #home every month" into a todo draft.
parse_quick_add in Python
1.0.0
py rs ts
44 tests
subscriptions.proration
Mid-cycle plan change: credit for unused time on the old plan and charge for the rest of the period on the new one.
prorate_change in Python
1.0.0
py rs ts
17 tests
monitor.alert-mute
Whether to hold an alert back: its component is under maintenance, or a related alert on it is already firing.
mute_alert in Python
1.0.0
py rs ts
19 tests
insurance.claim-reserve Unreviewed
Claim reserve history: paid, recovered, outstanding and incurred after each transaction, and the movement.
claim_reserve_history in Python
1.0.1
py rs ts
14 tests
invest.rebalance Unreviewed
Whole-unit buy and sell trades that bring a portfolio back to target weights, skipping trades below a minimum size.
rebalance in Python
1.0.1
py rs ts
22 tests
insurance.mid-term-adjustment Unreviewed
Additional or return premium for a mid-term policy change, pro rata on the days left, plus an admin fee.
mid_term_adjustment in Python
1.0.1
py rs ts
17 tests
monitor.burn-rate-alert
Multiwindow, multi-burn-rate SLO alerting: which rules fire, from event counts per window (Google SRE workbook).
burn_rate_alert in Python
2.0.0
py rs ts
30 tests
construction.roof-pitch
Roof pitch in degrees, rafter length and roof slope area from span, rise and length.
roof_pitch in Python
1.0.0
py rs ts
15 tests
1.0.0
py rs ts
14 tests
construction.retention
Retention held and released on a construction valuation: full rate, half at practical completion, none at the end.
retention in Python
1.0.0
py rs ts
17 tests
monitor.alert-rule
Evaluate a threshold alert rule over a metric series: inactive, pending, firing or no-data, Prometheus style.
evaluate_alert_rule in Python
1.0.0
py rs ts
25 tests
math.round-float
Round a float half away from zero to 0-12 decimal places, identically in TypeScript, Python and Rust.
round_float in Python
1.0.0
py rs ts
22 tests
retail.promotion-apply
Apply BOGOF, 3-for-2, percent off, amount off and multibuy deals to a basket, best for the customer, allocated to lines.
apply_promotions in Python
1.0.0
py rs ts
23 tests
charts.contrast
WCAG 2.x contrast ratio between two colours, and which text colour reads best on a background.
A group of 2: contrast_ratio, readable_text_color
1.0.0
py rs ts
22 tests
property.rent-review Unreviewed
New rent after an index-linked (CPI/RPI) rent review, with an optional collar and cap and upward-only option.
rent_review in Python
1.0.1
py rs ts
19 tests
retail.loyalty-points
Loyalty points for a purchase: redeem in blocks, earn on what is paid, with tier multipliers.
loyalty_points in Python
1.0.0
py rs ts
19 tests
construction.valuation
Interim valuation: gross value to date, retention, previous payments, amount due, VAT or reverse charge, and CIS.
interim_valuation in Python
1.0.0
py rs ts
16 tests
math.pow
base to the power exponent from + - * / only, exact by squaring for whole exponents, identical in every language.
pow in Python
1.0.0
py rs ts
16 tests
retail.price-rounding
Snap a price to a price point: charm pricing (.99, .95), nearest 5p or 10p, rounding up, down or to nearest.
round_price in Python
1.0.0
py rs ts
25 tests