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https://github.com/MBombeck/HealthLog.git
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BernhardBuckel
503f0f183a
Phase 2 of #1095: new code only, no behaviour change. Nothing imports it yet. An analyte lists its units as affine maps to a hub unit (hub = a * value + b), so any pair goes unit -> hub -> unit. Molar-mass factors are derived from the formula and a cited atomic-weight table instead of being typed; glucose reuses MGDL_PER_MMOL. HbA1c is the IFCC-NGSP master equation. Units that differ only by a power of ten convert for any analyte, inside one family and never across mass and amount. An entry with no source, a hub that is not one of its units, or a non-positive factor makes the registry fail to load. convertLabValue, convertLabRange and conversionsFor refuse rather than guess: unknown unit, unknown analyte, a mass to amount pair without an analyte key, a value that is not finite. Triglycerides, haemoglobin in mmol/L, ferritin and B12 in pmol/L and enzymes in ukat/L stay refusals. Refs #1095
51 lines
1.7 KiB
TypeScript
51 lines
1.7 KiB
TypeScript
/**
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* The atomic weights the molar-mass conversions are derived from.
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*
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* Conventional atomic weights as published by the IUPAC Commission on Isotopic
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* Abundances and Atomic Weights (CIAAW), "Standard atomic weights". Only the
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* elements a conversion in the registry needs are listed; one more element is
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* one more line here, with a conversion that uses it.
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*
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* A molar mass is summed from these, never typed, so a long decimal cannot be
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* copied wrong into a factor that then touches every reading of a marker.
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*/
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export const ATOMIC_WEIGHTS_SOURCE =
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"IUPAC CIAAW, Standard atomic weights (conventional values)";
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export const ATOMIC_WEIGHTS = {
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H: 1.008,
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C: 12.011,
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N: 14.007,
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O: 15.999,
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Ca: 40.078,
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} as const;
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export type Element = keyof typeof ATOMIC_WEIGHTS;
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/** Atoms per molecule, by element: urea is `{ C: 1, H: 4, N: 2, O: 1 }`. */
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export type Formula = Readonly<Partial<Record<Element, number>>>;
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/** g/mol of a formula, summed from `ATOMIC_WEIGHTS`. */
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export function molarMass(formula: Formula): number {
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let total = 0;
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for (const [element, count] of Object.entries(formula) as Array<
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[Element, number]
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>) {
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total += ATOMIC_WEIGHTS[element] * count;
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}
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// Summing decimals leaves float noise past the sixth place (180.15600000000001).
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return Math.round(total * 1e6) / 1e6;
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}
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/** `C6H12O6` for `{ C: 6, H: 12, O: 6 }`: for a citation, in a stable order. */
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export function formulaLabel(formula: Formula): string {
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const order: Element[] = ["C", "H", "N", "O", "Ca"];
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return order
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.filter((element) => (formula[element] ?? 0) > 0)
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.map((element) => {
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const count = formula[element]!;
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return count === 1 ? element : `${element}${count}`;
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})
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.join("");
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}
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