Support for querying within a polygon

examples/app.js

@@ -15,6 +15,7 @@ const qs = new MongoQS({
   custom: {
     bbox: 'geojson',
     near: 'geojson',
+    within: 'geojson',
   },
 });
 

examples/test.js

@@ -99,6 +99,34 @@ describe('Example App', () => {
       .end(done);
   });
 
+  it('returns places inside polygon', (done) => {
+    const polygon = [
+      5.9490966796875,
+      61.025705069868856,
+      5.987548828125,
+      60.994423108456154,
+      6.10565185546875,
+      60.98376689595989,
+      6.1962890625,
+      61.016390262027116,
+      6.115264892578125,
+      61.04964487995011,
+      5.969696044921875,
+      61.0516390483921,
+      5.9490966796875,
+      61.025705069868856,
+    ].join(',');
+
+    app.get(`${url}?within=${polygon}`)
+      .expect(200)
+      .expect((res) => {
+        assert.equal(res.body.length, 2);
+        assert.equal(res.body[0].name, 'Solrenningen');
+        assert.equal(res.body[1].name, 'Norddalshytten');
+      })
+      .end(done);
+  });
+
   it('returns places with any of the following tags', (done) => {
     app.get(`${url}?tags[]=Båt&tags[]=Stekeovn`)
       .expect(200)

index.js

@@ -27,6 +27,10 @@ module.exports = function MongoQS(options) {
     this.custom.near = this.customNear(this.custom.near);
   }
 
+  if (this.custom.within) {
+    this.custom.within = this.customWithin(this.custom.within);
+  }
+
   if (this.custom.after) {
     this.custom.after = this.customAfter(this.custom.after);
   }
@@ -100,6 +104,74 @@ module.exports.prototype.customNear = field => (query, point) => {
   }
 };
 
+module.exports.prototype.customWithin = field => (query, pointList) => {
+  const pointStrArr = pointList.split(',');
+
+  //need at least four points to make a polygon
+  if(pointStrArr.length < 8) {
+    return {};
+  }
+
+  //ensure even amount of points
+  if(pointStrArr.length % 2 !== 0) {
+    return {};
+  }
+
+  //convert every string to a float
+  var pointNumArr = [];
+
+  try {
+    pointStrArr.forEach(str => {
+      var num = parseFloat(str, 10);
+
+      //if float conversion fails from bad input, return empty
+      if(isNaN(num)) {
+        throw new Error('Invalid value passed as polygon coordinate')
+      }
+
+      pointNumArr.push(num);
+    })
+  } catch (err) {
+    return {}
+  }
+
+  //build our coordinates array
+  var coordinates = [];
+
+  try {
+    for(var i = 0 ; i < pointNumArr.length ; i = i + 2) {
+      //should never happen from previous check
+      if(i+1 >= pointNumArr.length) {
+        throw new Error("Odd number of points given")
+      }
+
+      coordinates.push([pointNumArr[i], pointNumArr[i+1]]);
+    }
+  } catch (err) {
+    return {}
+  }
+
+  // check if last coordinate matches first, if not go ahead an add first into list
+  var lastIndex = coordinates.length-1;
+  var firstLon = coordinates[0][0]
+  var firstLat = coordinates[0][1]
+  var lastLon = coordinates[lastIndex][0]
+  var lastLat = coordinates[lastIndex][1]
+
+  if (firstLon !== lastLon || firstLat !== lastLat) {
+    return {}
+  }
+
+  query[field] = {
+    $geoWithin: {
+      $geometry : {
+        type: 'Polygon',
+        coordinates: [coordinates]
+      }
+    }
+  }
+};
+
 function parseDate(value) {
   let date = value;
 
@@ -192,7 +264,7 @@ module.exports.prototype.parseString = function parseString(string, array) {
           break;
         default:
           break;
-      }
+        }
       break;
     default:
       ret.org = org = op + org;

test.js

@@ -43,6 +43,45 @@ describe('customBBOX()', () => {
   });
 });
 
+describe('customWithin()', () => {
+  it('does not return $geoWithin query for invalid polygon', () => {
+    [
+      // non matching first last
+      '1,1,2,2,2,3,1,2,2,2',
+      // not enough points
+      '1,1,2,2,2,3',
+      // odd length
+      '1,1,2,2,2,3,1',
+      // invalid value
+      '1,1,2,2,2,3,1,2,2,a',
+    ].forEach((polygon) => {
+      mqs.customWithin('gojson')(query, polygon);
+      assert.deepEqual(query, {});
+    });
+  });
+
+  it('returns $geoWithin query for valid polygon', () => {
+    const string = '1,1,2,2,2,3,1,2,1,1';
+    mqs.customWithin('geojson')(query, string);
+    assert.deepEqual(query, {
+      geojson: {
+        $geoWithin: {
+          $geometry: {
+            type: 'Polygon',
+            coordinates: [[
+              [1, 1],
+              [2, 2],
+              [2, 3],
+              [1, 2],
+              [1, 1],
+            ]],
+          },
+        },
+      },
+    });
+  });
+});
+
 describe('customNear()', () => {
   it('does not return $near query for invalid point', () => {
     ['0123', '0,'].forEach((bbox) => {
@@ -107,6 +146,45 @@ describe('customNear()', () => {
   });
 });
 
+describe('customWithin()', () => {
+  it('does not return $geoWithin query for invalid polygon', () => {
+    [
+      // non matching first last
+      '1,1,2,2,2,3,1,2,2,2',
+      // not enough points
+      '1,1,2,2,2,3',
+      // odd length
+      '1,1,2,2,2,3,1',
+      // invalid value
+      '1,1,2,2,2,3,1,2,2,a',
+    ].forEach((polygon) => {
+      mqs.customWithin('gojson')(query, polygon);
+      assert.deepEqual(query, {});
+    });
+  });
+
+  it('returns $geoWithin query for valid polygon', () => {
+    const string = '1,1,2,2,2,3,1,2,1,1';
+    mqs.customWithin('geojson')(query, string);
+    assert.deepEqual(query, {
+      geojson: {
+        $geoWithin: {
+          $geometry: {
+            type: 'Polygon',
+            coordinates: [[
+              [1, 1],
+              [2, 2],
+              [2, 3],
+              [1, 2],
+              [1, 1],
+            ]],
+          },
+        },
+      },
+    });
+  });
+});
+
 describe('customAfter()', () => {
   it('does not return after query for invalid date', () => {
     ['foo', '2015-13-40'].forEach((date) => {