Ignore geostationary "transits" to prevent infinite loop

jspredict.js

@@ -69,7 +69,7 @@
 
   // Npm
   if (typeof require !== 'undefined') {
-    var satellite = require('satellite.js').satellite;
+    var satellite = require('satellite.js');
     m_moment = require('moment');
   }
   // Meteor
@@ -148,13 +148,16 @@
       var iterations = 0;
 
       while (iterations < max_iterations && transits.length < maxTransits) {
-        transit = this._quickPredict(satrec, qth, time);
+        let transit = this._quickPredict(satrec, qth, time);
         if (!transit) {
           break;
         }
         if (transit.end > end.valueOf()) {
           break;
         }
+        if (transit.end === 0) { // Geostationary
+          break;
+        }
         if (transit.end > start.valueOf() && transit.maxElevation > minElevation) {
           transits.push(transit);
         }
@@ -385,7 +388,7 @@
 
     _gmst: function(date) {
       date = new Date(date.valueOf());
-      return satellite.gstimeFromDate(
+      return satellite.gstime(
         date.getUTCFullYear(),
         date.getUTCMonth() + 1, // months range 1-12
         date.getUTCDate(),

jspredict.test.js

@@ -0,0 +1,28 @@
+const jspredict = require('./jspredict');
+
+describe('transits', () => {
+  test('it computes predictable transits', () => {
+    const tle = "0 LEMUR-2 JEROEN\n1 40934U 15052E   15306.10048119  .00001740  00000-0  15647-3 0  9990\n2 40934   6.0033 141.2190 0010344 133.6141 226.4604 14.76056230  5130";
+    const qth = [15, 130, .1];
+    const transits = jspredict.transits(tle, qth, 1446516345242, 1446545135046, 2, 4);
+
+    // From the README.
+    const firstTransit = transits[0];
+    expect(firstTransit.start).toBeCloseTo(1446519623929.2715);
+    expect(firstTransit.end).toBeCloseTo(1446520436786.1265);
+    expect(firstTransit.maxElevation).toBeCloseTo(26.592307317708105);
+    expect(firstTransit.apexAzimuth).toBeCloseTo(173.4489444396936);
+    expect(firstTransit.maxAzimuth).toBeCloseTo(244.2708297009277);
+    expect(firstTransit.minAzimuth).toBeCloseTo(108.07476128814044);
+    expect(firstTransit.duration).toBeCloseTo(812856.8549804688);
+  });
+
+  test('it returns no transits for geostationary satellites', () => {
+    // INTELSAT 39 on Oct 31, 2019
+    // https://www.n2yo.com/satellite/?s=44476
+    const tle = "INTELSAT 39\n1 44476U 19049B   19304.31021668  .00000022  00000-0  00000+0 0  9995\n2 44476   0.0018 233.4327 0000272   5.2638 334.3170  1.00274937   908";
+    const qth = [20.5937, 78.9629, 0.840];
+    const transits = jspredict.transits(tle, qth, 1572562039000, 1572568039000, 2, 4);
+    expect(transits).toStrictEqual([]);
+  });
+});

package.json

@@ -30,7 +30,13 @@
   },
   "homepage": "https://github.com/nsat/jspredict",
   "dependencies": {
-    "moment": "^2.10.6",
-    "satellite.js": "^1.2.0"
+    "moment": "^2.24.0",
+    "satellite.js": "^3.0.1"
+  },
+  "devDependencies": {
+    "jest": "^24.9.0"
+  },
+  "scripts": {
+    "test": "jest"
   }
 }