Preparing pull request

index.js

@@ -1,6 +1,7 @@
 "use strict";
 
 var chroma = require('chroma-js')
+var WeakMap = require("es6-weak-map")
 
 // These `require` statements are all explicit
 // to keep the browserify build from breaking
@@ -13,11 +14,11 @@ var lists = {
   x11: require('./lib/colors/x11')
 }
 
-let cache = new WeakMap()
+var cache = new WeakMap()
 var namer = module.exports = function(color, options) {
   options = options || {}
 
-  const cacheKey = {color, options}
+  var cacheKey = {color, options}
   if (cache.has(cacheKey)) {
     return cache.get(cacheKey)
   }
@@ -33,7 +34,7 @@ var namer = module.exports = function(color, options) {
     }
     results[key] = lists[key]
       .map (function(name) {
-        name.distance = chroma.deltaE(color, chroma(name.hex))
+        name.distance = options.distance === 'deltaE' ? chroma.deltaE(color, chroma(name.hex)) : chroma.distance(color, chroma(name.hex))
         return name
       })
       .sort (function(a, b) {

package.json

@@ -32,6 +32,7 @@
     "mocha": "^6.1.4"
   },
   "dependencies": {
-    "chroma-js": "^1.3.4"
+    "chroma-js": "^1.3.4",
+    "es6-weak-map": "^2.0.3"
   }
 }

test/index.js

@@ -21,13 +21,20 @@ suite('namer', function () {
     assert.equal(names.basic[0].distance, 0)
   })
 
-  test('matches inexact colors', function() {
-    var names = namer('FF0001')
+  test('matches inexact colors with deltaE', function() {
+    var names = namer('FF0001', { distance: 'deltaE' })
     assert.equal(names.basic[0].hex, '#FF0000')
     assert.equal(names.basic[0].name, 'red')
     assert.equal(Math.floor(names.basic[0].distance*100), 13)
   })
 
+  test('matches inexact colors with deltaE', function() {
+    var names = namer('FF0001')
+    assert.equal(names.basic[0].hex, '#FF0000')
+    assert.equal(names.basic[0].name, 'red')
+    assert.equal(Math.floor(names.basic[0].distance*100), 25)
+  })
+
 
   test('matches exact colors', function() {
     var names = namer('0000FF')