Merge pull request #3 from brahn/fix-sjoin-with-duplicate-fieldnames

Fix sjoin with duplicate fieldnames

Author: chrispahm

package.json

@@ -1,6 +1,6 @@
 {
   "name": "spatialmerge",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "description": "Merging geospatial data in JS",
   "type": "module",
   "main": "./dist/spatialmerge.cjs.js",

src/helpers.js

@@ -1,33 +1,49 @@
-function mergeWith (object1, object2, lsuffix, rsuffix) {
-  const keys1 = Object.keys(object1)
-  const keys2 = Object.keys(object2)
+function findAllDuplicates(array) {
+  const uniq = new Set(array);
+  if (uniq.size === array.length) {
+    return [];
+  }
+  const duplicates = new Set()
+  for (const element of array) {
+    if (uniq.has(element)) {
+      uniq.delete(element);
+    } else {
+      duplicates.add(element);
+    }
+  }
+  return [...duplicates];
+}
+
+function mergeWith(leftFeatureProps, rightFeatureProps, lsuffix = 'left', rsuffix = 'right') {  
+  const keys1 = Object.keys(leftFeatureProps)
+  const keys2 = Object.keys(rightFeatureProps)
   const allKeys = [...keys1, ...keys2]
-  const uniq = [...new Set(allKeys)]
+  const duplicates = findAllDuplicates(allKeys)
   const feature = {}
-  if (allKeys.length === uniq.length) {
-    keys1.forEach(key => (feature[key] = object1[key]))
-    keys2.forEach(key => (feature[key] = object2[key]))
+  if (duplicates.length === 0) {
+    keys1.forEach(key => (feature[key] = leftFeatureProps[key]))
+    keys2.forEach(key => (feature[key] = rightFeatureProps[key]))
     return feature
   } else {
-    const duplicates = allKeys.filter(key => uniq.indexOf(key) === -1)
     keys1.forEach(key => {
       if (duplicates.indexOf(key) > -1) {
-        feature[key + '_' + lsuffix] = object1[key]
+        feature[key + '_' + lsuffix] = leftFeatureProps[key]
       } else {
-        feature[key] = object1[key]
+        feature[key] = leftFeatureProps[key]
       }
     })
     keys2.forEach(key => {
       if (duplicates.indexOf(key) > -1) {
-        feature[key + '_' + rsuffix] = object2[key]
+        feature[key + '_' + rsuffix] = rightFeatureProps[key]
       } else {
-        feature[key] = object1[key]
+        feature[key] = rightFeatureProps[key]
       }
     })
     return feature
   }
 }
 
 export {
+  findAllDuplicates,  // exported just for testing
   mergeWith
 }

src/merge.js

@@ -20,7 +20,10 @@ function merge (geojson1, geojsonOrDataFrame, options = {}) {
     try {
       geojson1 = clone(geojson1)
     } catch (e) {
-      throw new Error('Cloning input GeoJSON failed. Check for missing/empty geometries in the feature collection. Original @turf/clone error message:', e)
+      // @turf/clone probably failed due to 
+      // https://github.com/Turfjs/turf/issues/2314
+      // falling back to JSON.stringify / parse
+      geojson1 = JSON.parse(JSON.stringify(geojson1))
     }
   }