feat: validate latitude and longitude (#16)

It is now impossible to decode a position with an invalid
latitude or longitude.

There are two motivations for this change:

1. General correctness.

2. `@mapeo/mock-data` is currently generating invalid latitudes and
   longitudes because of the schema in this repo. That causes [some
   workarounds if you need valid coordinates][0], and I plan to add more
   tests that will require similar workarounds. I felt that fixing the
   problem here, at the source, was best.

[0]: https://github.com/digidem/comapeo-cloud/blob/d6ab53197ac3970ee8f287ddb30663a04c6449d1/test/add-alerts-endpoint.js#L240-L243

json/geometry.json

@@ -10,9 +10,20 @@
       "type": "array",
       "minItems": 2,
       "maxItems": 2,
-      "items": {
-        "type": "number"
-      }
+      "items": [
+        {
+          "type": "number",
+          "description": "longitude",
+          "minimum": -180,
+          "maximum": 180
+        },
+        {
+          "type": "number",
+          "description": "latitude",
+          "minimum": -90,
+          "maximum": 90
+        }
+      ]
     },
     "linearRing": {
       "title": "LinearRing",

src/index.ts

@@ -175,7 +175,22 @@ function validateRawCoords(rawCoords: number[]) {
   if (rawCoords.length % 2 !== 0) {
     throw new Error('`coordinates` must have an even number of elements')
   }
+  for (let i = 0; i < rawCoords.length; i++) {
+    if (i % 2 === 0) {
+      validateLongitude(rawCoords[i])
+    } else {
+      validateLatitude(rawCoords[i])
+    }
+  }
+}
+
+const rangeValidator = (max: number) => (value: number) => {
+  if (Math.abs(value) > max) {
+    throw new Error(`Coordinate value must be between -${max} and ${max}`)
+  }
 }
+const validateLatitude = rangeValidator(90)
+const validateLongitude = rangeValidator(180)
 
 function validateLinearRing(ring: Position[]): asserts ring is LinearRing {
   if (ring.length < 4) {

test/fixture/bad-proto/bad-latitude.json

@@ -0,0 +1,5 @@
+{
+  "type": "TYPE_POINT",
+  "coordinates": [123, 91],
+  "lengths": []
+}

test/fixture/bad-proto/bad-longitude.json

@@ -0,0 +1,5 @@
+{
+  "type": "TYPE_POINT",
+  "coordinates": [181, 12],
+  "lengths": []
+}

test/fixture/bad-proto/bad-type.json

@@ -1,5 +1,5 @@
 {
   "type": "TYPE_UNSPECIFIED",
-  "coordinates": [100, 102],
+  "coordinates": [123, 45],
   "lengths": []
 }

test/fixture/bad-proto/invalid-ring.json

@@ -1,5 +1,5 @@
 {
   "type": "TYPE_POLYGON",
-  "coordinates": [100, 101, 102, 103, 104, 105],
+  "coordinates": [1, 2, 3, 4, 5, 6],
   "lengths": []
 }

test/fixture/bad-proto/missing-coordinates.json

@@ -1,5 +1,5 @@
 {
   "type": "TYPE_POLYGON",
-  "coordinates": [100, 101, 102, 103, 104, 105, 106, 107],
+  "coordinates": [0, 1, 2, 3, 4, 5, 6, 7],
   "lengths": [5]
 }

test/fixture/bad-proto/odd-coordinates.json

@@ -1,5 +1,5 @@
 {
   "type": "TYPE_POINT",
-  "coordinates": [100, 101, 102],
+  "coordinates": [12, 34, 56],
   "lengths": []
 }

test/fixture/good-geojson/multipolygon-single.geojson

@@ -4,9 +4,9 @@
     [
       [
         [0, 0],
-        [100, 0],
-        [100, 100],
-        [0, 100],
+        [12, 0],
+        [123, 45],
+        [0, 12],
         [0, 0]
       ]
     ]

test/fixture/good-geojson/polygon-precision.geojson

@@ -2,11 +2,11 @@
   "type": "Polygon",
   "coordinates": [
     [
-      [5425435.733081569895148, 2012689.63544030720368],
-      [5425333.066045090556145, 2012658.8061882276088],
-      [5425324.357915714383125, 2012693.518385621719062],
-      [5425426.5193927353248, 2012720.238697179593146],
-      [5425435.733081569895148, 2012689.63544030720368]
+      [179.733081569895148, 89.63544030720368],
+      [179.066045090556145, 89.8061882276088],
+      [179.357915714383125, 89.518385621719062],
+      [179.5193927353248, 89.238697179593146],
+      [179.733081569895148, 89.63544030720368]
     ]
   ]
 }