Handle INF/NAN

compress.js

@@ -11,15 +11,28 @@ if (typeof Map == 'undefined' || !Object.entries) {
  * @param {array} value
  * @returns {Boolean} is this an array where all fields are numbers (including the empty array).
  */
-function isNumericArray(value) {
-    for (var i = 0; i < value.length; i++) {
-        if (typeof (value[i]) !== 'number') {
+function isNumericArray(array) {
+    for (var i = 0; i < array.length; i++) {
+        var v = array[i];
+        if (typeof (v) !== 'number') {
             return false;
         }
     }
     return true;
 }
 
+/**
+ * @param {string[]} array, possibly including Infinity/NaN
+ * @return {string} cache key identifying an array with those numbers.
+ */
+function createCacheKey(array) {
+    var parts = [];
+    for (var i = 0; i < array.length; i++) {
+        parts.push(String(array[i]));
+    }
+    return parts.join(',');
+}
+
 /**
  * Compress data returned by geobuf's decode function.
  * Objects are modified in place.
@@ -55,7 +68,7 @@ function compress(value, cache = new Map(), numericArrayCache = null) {
         // and experimentally appears to reduce capacity used.
         var result = value.slice();
         if (numericArrayCache && isNumericArray(result)) {
-            var cacheKey = JSON.stringify(result);
+            var cacheKey = createCacheKey(result);
             var cachedEntry = numericArrayCache.get(cacheKey);
             if (cachedEntry) {
                 cache.set(value, cachedEntry);

test/validate.test.js

@@ -139,7 +139,27 @@ test('can compress memory and deduplicate points', function (t) {
     t.same(polygon[0], [1, 0], 'should preserve value');
     t.end();
 });
+test('compress should handle infinite numbers', function (t) {
+    var INF = 1 / 0;
+    // JSON.stringify doesn't support INF
+    var original = [[INF], [-INF], [0], [0], [INF]];
+    var compressedData = geobuf.compress(original, new Map(), new Map());
+    t.same([[INF], [-INF], [0], [0], [INF]], compressedData);
+    t.strictEqual(compressedData[2], compressedData[3]);
+    t.strictEqual(compressedData[0], compressedData[4]);
+    t.end();
+});
+test('compress should handle NaN', function (t) {
+    var original = [[0, Number.NaN], [0, Number.NaN], [0, null]];
+    var compressedData = geobuf.compress(original, new Map(), new Map());
+    t.strictEqual(compressedData[0][0], 0);
+    t.strictEqual(compressedData[0], compressedData[1]);
+    t.same(compressedData[2], [0, null]);
+    t.ok(Number.isNaN(compressedData[0][1])); // Note that NaN !== NaN
+    t.end();
+});
 function roundtripTest(geojson) {
+
     return function (t) {
         var buf = geobuf.encode(geojson, new Pbf());
         var geojson2 = geobuf.decode(new Pbf(buf));