Pantry units and recipes: amounts in pounds, cups and so on, Use some, and Cooked it with a preview of what comes out

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

units.js

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+// Amounts and units for the pantry and recipes: read "1 1/2 cups all-purpose flour" into an amount, a unit and a name; convert between units (cups to pounds needs to know the
+// ingredient, so there is a table of common ones); show an amount nicely ("8 lb 15 oz"); and work out what cooking a recipe takes out of the pantry. Everything here is an estimate:
+// it is for keeping count of the flour, not for the lab.
+const VOL = { ml: 1, l: 1000, tsp: 4.92892, tbsp: 14.7868, 'fl oz': 29.5735, cup: 236.588, pint: 473.176, quart: 946.353, gallon: 3785.41, stick: 118.294 }; // to millilitres (a stick of butter is half a cup)
+const WT = { g: 1, kg: 1000, oz: 28.3495, lb: 453.592 };                                                                                                       // to grams
+const ALIAS = { c: 'cup', cups: 'cup', tablespoon: 'tbsp', tablespoons: 'tbsp', tbs: 'tbsp', tbl: 'tbsp', tbsps: 'tbsp', t: 'tsp', teaspoon: 'tsp', teaspoons: 'tsp', tsps: 'tsp', ounce: 'oz', ounces: 'oz', ozs: 'oz', pound: 'lb', pounds: 'lb', lbs: 'lb', gram: 'g', grams: 'g', gr: 'g', kilogram: 'kg', kilograms: 'kg', kgs: 'kg', milliliter: 'ml', milliliters: 'ml', millilitre: 'ml', millilitres: 'ml', liter: 'l', liters: 'l', litre: 'l', litres: 'l', pt: 'pint', pints: 'pint', qt: 'quart', quarts: 'quart', gal: 'gallon', gallons: 'gallon', floz: 'fl oz', 'fl. oz': 'fl oz', 'fl oz.': 'fl oz', sticks: 'stick' };
+/** The canonical unit for a word ("Cups" -> "cup", "lbs." -> "lb"), or '' when it is not a unit this knows. */
+function unitOf(w) { const s = String(w || '').toLowerCase().trim().replace(/\.$/, ''); if (VOL[s] || WT[s]) return s; return ALIAS[s] || ''; }
+const family = u => WT[u] ? 'weight' : VOL[u] ? 'volume' : 'count';
+const UNITS = ['', 'g', 'kg', 'oz', 'lb', 'ml', 'l', 'tsp', 'tbsp', 'cup', 'fl oz', 'pint', 'quart', 'gallon'];
+
+// grams in one cup, for the things people bake and cook with (King Arthur, USDA). The longest matching name wins ("brown sugar" before "sugar").
+const DENSITY = { flour: 120, 'bread flour': 120, 'whole wheat flour': 120, 'almond flour': 96, 'coconut flour': 112, 'rice flour': 158, sugar: 200, 'brown sugar': 213, 'powdered sugar': 120, 'confectioners sugar': 120, 'icing sugar': 120, butter: 227, margarine: 227, shortening: 190, milk: 245, buttermilk: 245, cream: 238, 'heavy cream': 238, 'half and half': 242, water: 237, juice: 248, oil: 218, 'olive oil': 216, 'vegetable oil': 218, 'coconut oil': 218, honey: 340, molasses: 340, 'maple syrup': 322, 'corn syrup': 328, syrup: 322, rice: 185, 'brown rice': 190, quinoa: 170, oats: 90, oatmeal: 90, cornmeal: 157, cornstarch: 128, cocoa: 85, 'cocoa powder': 85, salt: 288, 'baking powder': 230, 'baking soda': 230, yeast: 144, 'peanut butter': 258, 'almond butter': 250, 'cream cheese': 227, 'sour cream': 240, yogurt: 245, 'chocolate chips': 170, raisins: 145, nuts: 120, almonds: 140, walnuts: 117, pecans: 109, cheese: 113, parmesan: 100, breadcrumbs: 108, lentils: 192, beans: 190, pasta: 100, mayonnaise: 220, ketchup: 240, 'tomato sauce': 245, 'chicken broth': 240, broth: 240, stock: 240, vinegar: 239, 'soy sauce': 255, coconut: 80, 'cottage cheese': 226, ricotta: 246, 'peanuts': 146, 'sunflower seeds': 140, 'chia seeds': 170, flaxseed: 168 };
+const stem = w => w.replace(/(ies)$/, 'y').replace(/(ves)$/, 'f').replace(/(es|s)$/, '');
+const words = t => (String(t).toLowerCase().replace(/&/g, ' and ').match(/[a-z]+/g) || []).map(stem);
+/** Grams per cup for a named ingredient, or 0 when it is not in the table. */
+function density(name) {
+  const have = new Set(words(name)); let best = 0, bestLen = 0;
+  for (const [k, g] of Object.entries(DENSITY)) { const ks = words(k); if (ks.length >= bestLen && ks.every(w => have.has(w)) && (ks.length > bestLen || !best)) { best = g; bestLen = ks.length; } }
+  return best;
+}
+const FR = { '¼': 0.25, '½': 0.5, '¾': 0.75, '⅓': 1 / 3, '⅔': 2 / 3, '⅛': 0.125, '⅜': 0.375, '⅝': 0.625, '⅞': 0.875, '⅕': 0.2, '⅖': 0.4, '⅗': 0.6, '⅘': 0.8, '⅙': 1 / 6, '⅚': 5 / 6 };
+/** A leading amount ("1 1/2", "½", "1½", "2-3", "2 to 3", "0.5"): { n, rest } or null. A range counts as its middle. */
+function leadingNumber(text) {
+  let s = String(text || '').trim().replace(/[¼½¾⅓⅔⅛⅜⅝⅞⅕⅖⅗⅘⅙⅚]/g, m => ' ' + FR[m] + ' ').replace(/\s+/g, ' ').trim();
+  const one = /^(\d+\s+\d+\/\d+|\d+\/\d+|\d+\.\d+|\d+\s+0?\.\d+|\d+|0?\.\d+)/.exec(s); if (!one) return null;
+  const val = t => { t = t.trim(); let m; if ((m = /^(\d+)\s+(\d+)\/(\d+)$/.exec(t))) return +m[1] + +m[2] / +m[3]; if ((m = /^(\d+)\/(\d+)$/.exec(t))) return +m[1] / +m[2]; if ((m = /^(\d+)\s+(0?\.\d+)$/.exec(t))) return +m[1] + +m[2]; return parseFloat(t); };
+  let n = val(one[1]), rest = s.slice(one[0].length).trim(); const range = /^(?:-|–|to)\s*(\d+\s+\d+\/\d+|\d+\/\d+|\d+\.\d+|\d+|0?\.\d+)/i.exec(rest); if (range) { n = (n + val(range[1])) / 2; rest = rest.slice(range[0].length).trim(); }
+  return isFinite(n) ? { n, rest } : null;
+}
+/** One recipe line -> { amount (number or null), unit ('' for a count), name }. "2 (14 oz) cans tomatoes" is 28 oz of tomatoes. */
+function parseIngredient(text) {
+  const t = String(text || '').trim(), q = leadingNumber(t); if (!q) return { amount: null, unit: '', name: t };
+  let amount = q.n, rest = q.rest, unit = '', m;
+  if ((m = /^\(\s*([\d./\s]+)\s*([a-z. ]+?)\s*\)\s*/i.exec(rest)) && unitOf(m[2])) { const inner = leadingNumber(m[1]); if (inner) { amount = q.n * inner.n; unit = unitOf(m[2]); rest = rest.slice(m[0].length).replace(/^(cans?|jars?|packages?|pkgs?|bags?|boxes|box|bottles?|containers?)\b\s*/i, '').trim(); } }
+  else { const two = /^(fl\.?\s?oz\.?)\b/i.exec(rest); if (two) { unit = 'fl oz'; rest = rest.slice(two[0].length).trim(); } else if ((m = /^T(\s|$)/.exec(rest))) { unit = 'tbsp'; rest = rest.slice(m[0].length).trim(); } // (a capital T is a tablespoon, a small t a teaspoon)
+  else if ((m = /^([a-zA-Z]+\.?)(\s|$)/.exec(rest)) && unitOf(m[1]) && !(m[1].length === 1 && /^[a-z]$/.test(m[1]) && !/^[ctT]$/.test(m[1]))) { unit = unitOf(m[1]); rest = rest.slice(m[0].length).trim(); } }
+  rest = rest.replace(/^of\s+/i, '').replace(/\(.*?\)/g, ' ').replace(/,.*$/, '').replace(/\s+/g, ' ').trim();
+  return { amount, unit, name: rest || t };
+}
+/** Convert an amount between units. Weight and volume need the ingredient (a name, or grams per cup); a count converts only to a count. Returns null when it cannot. */
+function convert(amount, from, to, name, gPerCup) {
+  if (from === to) return amount; const ff = family(from), tf = family(to);
+  if (ff === 'count' || tf === 'count') return null;
+  if (ff === tf) { const t = ff === 'weight' ? WT : VOL; return amount * t[from] / t[to]; }
+  const g = gPerCup || density(name); if (!g) return null; const gPerMl = g / VOL.cup;
+  return ff === 'volume' ? amount * VOL[from] * gPerMl / WT[to] : amount * WT[from] / gPerMl / VOL[to];
+}
+const r2 = n => Math.round(n * 100) / 100, r4 = n => Math.round(n * 10000) / 10000; // (amounts keep four decimals: a spoonful of butter is a few hundredths of a pound)
+/** An amount to show: "8 lb 15 oz", "2 1/2 cups", "12". */
+function fmt(qty, unit) {
+  if (qty == null) return ''; const q = Math.round(qty * 100) / 100;
+  if (unit === 'lb' && q % 1) { let lb = Math.floor(q), oz = Math.round((q - lb) * 16); if (oz === 16) { lb++; oz = 0; } return oz ? `${lb ? lb + ' lb ' : ''}${oz} oz` : lb + ' lb'; }
+  if ((unit === 'gallon' || unit === 'quart') && q % 1) { // a fraction of a gallon or quart is easier to picture in smaller measures: "3 qt 2 1/2 cups"
+    let cups = Math.round(q * (unit === 'gallon' ? 16 : 4) * 4) / 4; const parts = []; if (unit === 'gallon') { const g = Math.floor(cups / 16); if (g) parts.push(g + ' gal'); cups -= g * 16; } const qt = Math.floor(cups / 4); if (qt) parts.push(qt + ' qt'); cups -= qt * 4;
+    if (cups) { const w = Math.floor(cups), f = { 0.25: '1/4', 0.5: '1/2', 0.75: '3/4' }[cups - w]; parts.push(`${w ? w + ' ' : ''}${f || ''}`.trim() + (cups > 1 ? ' cups' : ' cup')); } return parts.join(' ') || '0';
+  }
+  const frac = q % 1, whole = Math.floor(q), nice = { 0.25: '1/4', 0.33: '1/3', 0.5: '1/2', 0.67: '2/3', 0.75: '3/4' }[r2(frac)];
+  const num = ['cup', 'tbsp', 'tsp', 'quart', 'pint', 'gallon'].includes(unit) && nice ? `${whole ? whole + ' ' : ''}${nice}` : String(q);
+  return unit ? `${num} ${unit === 'cup' && q > 1 ? 'cups' : unit}` : num;
+}
+const aboutWords = (a, b) => { const ws = new Set(words(a)); return words(b).length > 0 && words(b).every(w => ws.has(w)); };
+/** What cooking `ingredients` (lines, or { amount, unit, name }) takes out of the pantry `items` (each { id, name, qty, unit }), times `scale`.
+ *  Returns [{ line, item, take (in the item's own unit), unit, left, ok, why }]. Lines that match nothing in the pantry are not listed. */
+function plan(ingredients, items, scale = 1) {
+  const out = [], left = new Map(items.map(x => [x.id, x.qty]));
+  for (const raw of ingredients) {
+    const ing = typeof raw === 'string' ? { ...parseIngredient(raw), line: raw } : { ...raw, line: raw.line || [raw.amount, raw.unit, raw.name].filter(x => x != null && x !== '').join(' ') };
+    let best = null; for (const it of items) if (aboutWords(ing.name, it.name) && (!best || words(it.name).length > words(best.name).length)) best = it; if (!best) continue;
+    const row = { line: ing.line, item: { id: best.id, name: best.name }, unit: best.unit || '', ok: false, take: 0, left: null, why: '' };
+    if (best.qty == null) { row.why = 'not counted'; out.push(row); continue; }
+    if (ing.amount == null) { row.why = 'no amount in the recipe (“to taste”)'; out.push(row); continue; }
+    const a = ing.amount * (scale || 1), fromU = ing.unit, toU = best.unit || '';
+    let take = fromU === '' && toU === '' ? a : fromU !== '' && toU !== '' ? convert(a, fromU, toU, best.name + ' ' + ing.name) : null;
+    if (take == null) row.why = fromU === '' ? `the recipe counts ${best.name.toLowerCase()} but the pantry has it in ${toU}` : toU === '' ? `the recipe uses ${fromU} but the pantry counts ${best.name.toLowerCase()}` : `cannot turn ${fromU} into ${toU} for ${best.name.toLowerCase()}`;
+    else { take = r4(take); const now = left.get(best.id); row.ok = true; row.take = take; row.left = Math.max(0, r4(now - take)); left.set(best.id, row.left); if (take > now) row.why = 'more than the pantry has'; }
+    out.push(row);
+  }
+  return out;
+}
+module.exports = { UNITS, unitOf, family, density, leadingNumber, parseIngredient, convert, fmt, plan, words };