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Five functions, taken out of the calendar.

A calendar has to solve some genuinely annoying problems that have nothing to do with calendars: what a recurrence rule means and how to write one, what easing a spring makes, which words in a sentence were a date, when everyone is awake at once. kloq solves all of them as pure, exported, tested functions — so here they are as pages, free, with nothing to sign up for.

Each page runs the real export, not a copy. If a tool here gets something wrong, the calendar gets it wrong too — which is a good reason for us to keep them honest.

01the tools

Pick one.

stiffness · damping · samples → one CSS value

Spring to CSS linear() converter

cubic-bezier() cannot overshoot, so it cannot describe a spring. linear() can: sample the spring once, and the curve rides along in a stylesheet with no physics engine at runtime. Drag the sliders, watch the block, copy the value.

Open it

RFC 5545 in, plain English and real dates out

RRULE explainer

FREQ=MONTHLY;BYDAY=-1FR is a sentence written for a parser, not a person. Paste one in and get the sentence back in English, with the dates it actually produces.

Open it

a sentence in, an event and its source offsets out

Natural-language date parser

Most natural-language date parsers hand you a result and leave you guessing which words they used. This one reports the exact source offsets of every phrase it consumed, so the input can underline itself while you type.

Open it

controls in, a valid RRULE out

RRULE builder

Writing an RRULE by hand means reading RFC 5545 to find out that the last Friday of the month is BYDAY=-1FR. Pick it from a menu instead, and watch the rule and the dates it produces update as you go.

Open it

day, night, and the hours everyone is awake

Time zone overlap map

Not a map of the world — a map of the day. Each row is one zone's next 24 hours on a shared timeline, so night steps across the rows the way a terminator sweeps a globe, and the hours where everyone is awake are the ones worth booking.

Open it

02the calendar they came from

All five ship inside one React component.

Recurrence, quick add, the zone layer and the spring sampler are all exported from kloq alongside the calendar itself — free on npm, or as commercially licensed source.

Open the live demo