Functional Weave
Code in TypeScript

Every capability

Ordered by level: primitives at the bottom of the graph, workflows at the top. Each one carries its own tests, at least 8 per function.

Suites — the capabilities a kind of app is built from: accounting, payroll, an online shop, a clinic…

Collection: React form elements — accessible form components for React, and the pure helpers they use.

Level 0 primitive

charts.color
Hex colours to RGB and back, and sRGB channels to linear light and back, identically in every language.
A group of 4: parseHex, toHex, srgbToLinear, linearToSrgb
logistics.sscc
Build an 18-digit SSCC pallet label number from extension digit, GS1 company prefix and serial, with its check digit.
buildSscc in TypeScript
math.exp
e to the power x from + - * / only, so TypeScript, Python and Rust return the same double for the same input.
exp in TypeScript
math.sin-cos
Sine and cosine of an angle in radians from + - * / only, so every language returns the same doubles.
sinCos in TypeScript
validation.gtin
Check an EAN-8, UPC-A, EAN-13 or GTIN-14 barcode number against the GS1 mod-10 check digit.
validateGtin in TypeScript
charts.extent
The minimum and maximum of a series as [min, max], skipping gaps (null), or null when there is no value.
extent in TypeScript
math.ln
Natural logarithm from + - * / only, so TypeScript, Python and Rust return the same double for the same input.
ln in TypeScript
math.basis-points
Convert a rate between percent, basis points and a plain ratio exactly, as decimal text or integer basis points.
A group of 3: convertRate, toBasisPoints, fromBasisPoints
crypto.sha256
The SHA-256 digest of a byte string (FIPS 180-4), in pure code that also runs in the browser.
sha256 in TypeScript
encoding.base64
Bytes to base64 and base64url text and back (RFC 4648), with strict decoding, identically in every language.
A group of 4: base64Encode, base64Decode, base64UrlEncode, base64UrlDecode
encoding.hex
Bytes to lowercase hexadecimal text and back (RFC 4648 base16), strictly, identically in every language.
A group of 2: hexEncode, hexDecode
encoding.utf8
Text to UTF-8 bytes and strictly back (RFC 3629), so hashing and signing see the same bytes in every language.
A group of 2: utf8Encode, utf8Decode

Level 1 generic concept

charts.scale
Map data values onto screen positions and back: linear, log, time, band and point scales, and nice domains.
A group of 7: linearScale, invertLinear, niceDomain, logScale, timeScale, bandScale, pointScale
health.egfr Unreviewed
eGFR in mL/min/1.73 m² by the race-free CKD-EPI 2021 creatinine equation, from creatinine in µmol/L or mg/dL.
egfrCkdEpi2021 in TypeScript
fleet.emissions
Vehicle greenhouse gas emissions (grams CO2e) from fuel used or distance, using UK government DESNZ conversion factors.
fleetEmissions in TypeScript
math.rational
Exact fraction arithmetic, always reduced, for rates and ratios that must not drift.
A group of 8: calculateRational, rational, addRational, subtractRational, multiplyRational, divideRational, compareRational, rationalToInteger
money.compare
Compare two amounts of one currency, refusing to compare across currencies; min, max and clamp too.
A group of 4: compareMoney, minMoney, maxMoney, clampMoney
money.sum
Total a list of monetary amounts, with an explicit currency for the empty case.
sumMoney in TypeScript
auth.jwt
Sign, verify and decode HS256 JSON Web Tokens (RFC 7519): signature, algorithm and exp/nbf/iat checked with leeway.
A group of 3: signJwt, verifyJwt, decodeJwt
charts.format
Axis and label text for charts: tick numbers, SI prefixes (1.2k, 3.4M), percentages, dates and money.
A group of 5: formatTick, formatSi, formatPercent, formatDate, formatMoneyTick

Level 2 domain function

finance.tax.vat-rate Unreviewed
Look up the VAT rate in force for a jurisdiction, category and date.
vatRate in TypeScript
finance.tax.remove-vat Unreviewed
Extract the VAT already included in a gross amount, using the rate in force on the date of supply.
removeVat in TypeScript
charts.shape
SVG path strings for lines, areas, steps, monotone curves, bars, arcs and pie slices, identical in every language.
A group of 7: linePath, areaPath, stepPath, monotoneCurve, barRects, arcPath, pieAngles
todo.group-by-due
Split todos into Overdue, Today, Tomorrow, This week, Later, No date and Done sections, in that order.
A group of 2: groupByDue, groupByDueWithOrder
retail.oss-vat
EU distance-selling VAT: which member state's standard rate applies under OSS and the EUR 10,000 threshold, and the VAT.
ossVat in TypeScript
invest.bond-yield Unreviewed
Current yield and yield to maturity of a fixed-coupon bond from its clean price, as Excel's YIELD defines it.
bondYield in TypeScript
charts.layout
Chart layout: the plot area inside margins, legend items wrapped into rows, and greedy label collision avoidance.
A group of 3: plotArea, legendRows, avoidCollisions
auth.access-token
Issue an API's HS256 access token, read one from an Authorization header, and refuse revoked or superseded ones.
A group of 3: issueAccessToken, readAccessToken, confirmAccessToken
dates.uk-tax-year
The UK personal tax year containing a date: 6 April to 5 April, with HMRC's label.
ukTaxYear in TypeScript

Level 3 business operation