init

public/calculators/nmea.js

@@ -0,0 +1,22 @@
+import {revive, persist, labelInput} from '/js/util.js';
+export default {
+  id:'nmea', name:'NMEA 0183 Checksum', about:'Paste without the leading $ and without *XX.',
+  render(root){
+    const key='calc_nmea_v1';
+    const s = revive(key,{sentence:'GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,', expected:''});
+    const ui = document.createElement('div');
+    ui.append(labelInput('Sentence (no $ and no *XX)','text','sentence', s.sentence), labelInput('Expected checksum (optional, hex)','text','expected', s.expected,{placeholder:'e.g. 47'}));
+    const out = document.createElement('div'); out.className='result'; ui.append(out);
+    function checksum(str){ let x=0; for(const ch of str) x ^= ch.charCodeAt(0); return x; }
+    function calc(){
+      const sentence = ui.querySelector('[name=sentence]').value.trim();
+      const exp = ui.querySelector('[name=expected]').value.trim();
+      const sum = checksum(sentence);
+      const hex = sum.toString(16).toUpperCase().padStart(2,'0');
+      let html = `<div><strong>Computed:</strong> <code class="k">*${hex}</code></div>`;
+      if(exp){ const ok = hex === exp.toUpperCase(); html += `<div>${ok ? 'Match' : 'Mismatch'} (expected <code class="k">*${exp.toUpperCase()}</code>)</div>`; }
+      out.innerHTML = html; persist(key,{sentence, expected:exp});
+    }
+    ui.addEventListener('input', calc); calc(); root.append(ui);
+  }
+}