Merge pull request #897 from Turfjs/transform-scale-#895

Add FeatureCollection mutate tests (not failing)

packages/turf-hex-grid/index.js

@@ -115,7 +115,7 @@ function hexagon(center, rx, ry) {
         vertices.push([x, y]);
     }
     //first and last vertex must be the same
-    vertices.push(vertices[0]);
+    vertices.push(vertices[0].slice());
     return polygon([vertices]);
 }
 

packages/turf-transform-scale/index.js

@@ -1,4 +1,5 @@
 var meta = require('@turf/meta');
+var clone = require('@turf/clone');
 var center = require('@turf/center');
 var helpers = require('@turf/helpers');
 var centroid = require('@turf/centroid');
@@ -12,6 +13,7 @@ var coordEach = meta.coordEach;
 var featureEach = meta.featureEach;
 var getCoord = invariant.getCoord;
 var getCoords = invariant.getCoords;
+var getGeomType = invariant.getGeomType;
 
 
 /**
@@ -39,7 +41,7 @@ module.exports = function (geojson, factor, origin, mutate) {
     var originIsPoint = Array.isArray(origin) || typeof origin === 'object';
 
     // Clone geojson to avoid side effects
-    if (mutate !== true) geojson = JSON.parse(JSON.stringify(geojson));
+    if (mutate !== true) geojson = clone(geojson);
 
     // Scale each Feature separately
     if (geojson.type === 'FeatureCollection' && !originIsPoint) {
@@ -56,21 +58,21 @@ module.exports = function (geojson, factor, origin, mutate) {
  * Scale Feature/Geometry
  *
  * @private
- * @param {Feature|Geometry} geojson GeoJSON Feature/Geometry
+ * @param {Feature|Geometry} feature GeoJSON Feature/Geometry
  * @param {number} factor of scaling, positive or negative values greater than 0
  * @param {string|Geometry|Feature<Point>|Array<number>} [origin="centroid"] Point from which the scaling will occur (string options: sw/se/nw/ne/center/centroid)
  * @returns {Feature|Geometry} scaled GeoJSON Feature/Geometry
  */
-function scale(geojson, factor, origin) {
+function scale(feature, factor, origin) {
     // Default params
-    var isPoint = (geojson.type === 'Point' || geojson.geometry && geojson.geometry.type === 'Point');
-    origin = defineOrigin(geojson, origin);
+    var isPoint = getGeomType(feature) === 'Point';
+    origin = defineOrigin(feature, origin);
 
     // Shortcut no-scaling
-    if (factor === 1 || isPoint) return geojson;
+    if (factor === 1 || isPoint) return feature;
 
     // Scale each coordinate
-    coordEach(geojson, function (coord) {
+    coordEach(feature, function (coord) {
         var originalDistance = rhumbDistance(origin, coord);
         var bearing = rhumbBearing(origin, coord);
         var newDistance = originalDistance * factor;
@@ -80,7 +82,7 @@ function scale(geojson, factor, origin) {
         if (coord.length === 3) coord[2] *= factor;
     });
 
-    return geojson;
+    return feature;
 }
 
 /**

packages/turf-transform-scale/package.json

@@ -37,6 +37,7 @@
   },
   "homepage": "https://github.com/Turfjs/turf",
   "devDependencies": {
+    "@turf/hex-grid": "^4.6.1",
     "@turf/truncate": "^4.6.0",
     "benchmark": "^2.1.4",
     "load-json-file": "^2.0.0",
@@ -47,6 +48,7 @@
     "@turf/bbox": "^4.6.0",
     "@turf/center": "^4.6.1",
     "@turf/centroid": "^4.6.1",
+    "@turf/clone": "^4.6.1",
     "@turf/helpers": "^4.6.0",
     "@turf/invariant": "^4.6.0",
     "@turf/meta": "^4.6.0",

packages/turf-transform-scale/test.js

@@ -4,6 +4,7 @@ const path = require('path');
 const load = require('load-json-file');
 const write = require('write-json-file');
 const center = require('@turf/center');
+const hexGrid = require('@turf/hex-grid');
 const truncate = require('@turf/truncate');
 const turfBBox = require('@turf/bbox');
 const centroid = require('@turf/centroid');
@@ -95,6 +96,34 @@ test('scale -- mutated input', t => {
     t.end();
 });
 
+test('scale -- mutated FeatureCollection', t => {
+    const line = featureCollection([
+        lineString([[10, 10], [12, 15]]),
+        lineString([[15, 15], [22, 35]]),
+        lineString([[30, 30], [42, 45]])
+    ]);
+    const lineBefore = JSON.parse(JSON.stringify(line));
+    scale(line, 1.5);
+    t.deepEqual(line, lineBefore, 'mutate = undefined - input should NOT be mutated');
+    scale(line, 1.5, 'centroid', false);
+    t.deepEqual(line, lineBefore, 'mutate = false - input should NOT be mutated');
+    scale(line, 1.5, 'centroid', 'nonBoolean');
+    t.deepEqual(line, lineBefore, 'non-boolean mutate - input should NOT be mutated');
+    t.end();
+});
+
+test('scale -- Issue #895', t => {
+    const grid = hexGrid([-122.930, 45.385, -122.294, 45.772], 5, 'miles');
+    featureEach(grid, (feature, index) => {
+        const factor = (index % 2 === 0) ? 0.4 : 0.6;
+        scale(feature, factor, 'centroid', true);
+    });
+    const output = directories.out + 'issue-#895.geojson';
+    if (process.env.REGEN) write.sync(output, grid);
+    t.deepEqual(grid, load.sync(output));
+    t.end();
+});
+
 test('scale -- geometry support', t => {
     const pt = point([10, 10]);
     const line = lineString([[10, 10], [12, 15]]);