Fix 3-col calculator labelling and add lint

hdyc-svelte/package.json

@@ -10,7 +10,8 @@
 		"start": "node build",
 		"prepare": "svelte-kit sync || echo ''",
 		"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
-		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch"
+		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
+		"lint:3col": "node scripts/lint-3col.mjs"
 	},
 	"devDependencies": {
 		"@sveltejs/adapter-node": "^5.5.4",

hdyc-svelte/scripts/lint-3col.mjs

@@ -0,0 +1,36 @@
+#!/usr/bin/env node
+import { readFileSync } from 'fs';
+import path from 'path';
+
+const file = path.resolve('src/lib/data/calculators.ts');
+const text = readFileSync(file, 'utf8');
+const start = text.indexOf('[');
+const end = text.indexOf('];', start);
+if (start === -1 || end === -1) {
+  console.error('Unable to locate calculators array in calculators.ts');
+  process.exit(1);
+}
+let arr = text.slice(start, end + 1).trim();
+arr = arr.replace(/,\s*\]$/, ']');
+let calculators;
+try {
+  calculators = JSON.parse(arr);
+} catch (err) {
+  console.error('Failed to parse calculators.ts as JSON:', err.message);
+  process.exit(1);
+}
+
+const offenders = calculators.filter(c =>
+  ['3col', '3col-mul'].includes(c.type) &&
+  c.name.toLowerCase().includes(' to ') &&
+  (!c.labels?.in3 || c.labels.in3.toLowerCase() === 'result')
+);
+
+if (offenders.length) {
+  console.error(`3-col calculators with vague or missing output labels: ${offenders.length}`);
+  offenders.slice(0, 20).forEach(c => console.error(`- ${c.slug}`));
+  if (offenders.length > 20) console.error(`…and ${offenders.length - 20} more`);
+  process.exit(1);
+}
+
+console.log('3-col label lint passed.');

hdyc-svelte/src/routes/[slug]/+page.svelte

@@ -11,7 +11,9 @@
   $: calc = data.calculator;
   $: related = data.related;
   $: pageTitle = `${calc.name} — ${SITE_NAME}`;
-  $: pageDescription = `Convert ${calc.labels.in1} to ${calc.labels.in2} instantly with our free online calculator. Accurate bidirectional conversion with the exact formula shown.`;
+  $: pageDescription = ['3col', '3col-mul'].includes(calc.type)
+    ? `Compute ${calc.labels.in3 ?? 'the derived value'} using ${calc.labels.in1} and ${calc.labels.in2}. Enter any two fields to solve the third.`
+    : `Convert ${calc.labels.in1} to ${calc.labels.in2} instantly with our free online calculator. Accurate two-way conversion with the exact formula shown.`;
   $: seo = buildSeoMeta({
     title: pageTitle,
     description: pageDescription,

migrate.py

@@ -187,6 +187,11 @@ def process():
             except:
                 pass
 
+        # Give 3-col calculators honest display names instead of "A to B"
+        if c_type in ['3col', '3col-mul'] and split_conversion_name(display_name):
+            op = '*' if c_type == '3col-mul' else '/'
+            display_name = f"{in1} {op} {in2}"
+
         # Avoid escaping single quotes by using JSON or dict
         entry = {
             'slug': slug,
@@ -200,11 +205,16 @@ def process():
         # Determine labels
         labels = {'in1': in1, 'in2': in2}
         if c_type in ['3col', '3col-mul']:
-            # generic 3rd label
-            if 'watts' in slug and 'amps' in slug: labels['in3'] = 'Volts'
-            elif 'lumens' in slug: labels['in3'] = 'Area (sq m)'
-            elif 'moles' in slug: labels['in3'] = 'Molar Mass'
-            else: labels['in3'] = 'Result'
+            # generic 3rd label; make it descriptive instead of the vague "Result"
+            if 'watts' in slug and 'amps' in slug:
+                labels['in3'] = 'Volts'
+            elif 'lumens' in slug:
+                labels['in3'] = 'Area (sq m)'
+            elif 'moles' in slug:
+                labels['in3'] = 'Molar Mass'
+            else:
+                op = '*' if c_type == '3col-mul' else '/'
+                labels['in3'] = f"{in1} {op} {in2}"
 
         if custom_labels:
             labels = custom_labels