Twig filter 'ksort': new filter

doc/TwigJS.md

@@ -71,6 +71,7 @@ Extra filters:
 * filter `osmParseDate`: returns an array with the lower and upper boundary of the year of a `start_date` tag. See [https://github.com/plepe/openstreetmap-date-parser](openstreetmap-date-parser) for details.
 * filter `osmFormatDate`: returns the date as localized strings. Accept an object for options, e.g. `{{ tags.start_date|osmFormatDate({ format: 'short' }) }}`. See [https://github.com/plepe/openstreetmap-date-format](openstreetmap-date-format) for details.
 * filter `natsort`: Sort an array naturally, see [https://www.npmjs.com/package/natsort](natsort) for details.
+* filter `ksort`: Sort an associative array by key (alphabetic)
 * filter `unique`: Remove duplicate elements from an array.
 * filter `md5`: calculate md5 hash of a string.
 * filter `enumerate`: enumerate the given list, e.g. "foo, bar, and bla". Input either an array (`[ "foo", "bar", "bla" ]|enumerate`) or a string with `;` as separator (`"foo;bar;bla"|enumerate`).

src/twigFunctions.js

@@ -122,6 +122,17 @@ function enumerate (list) {
 }
 OverpassLayer.twig.extendFunction('enumerate', (list) => enumerate(list))
 OverpassLayer.twig.extendFilter('enumerate', (list) => enumerate(list))
+OverpassLayer.twig.extendFilter('ksort', (list) => {
+  if (Array.isArray(list)) {
+    return list
+  }
+
+  let keys = list._keys || Object.keys(list)
+  keys.sort()
+  let result = Object.assign({}, list)
+  result._keys = keys
+  return result
+})
 OverpassLayer.twig.extendFunction('debug', function () {
   console.log.apply(null, arguments)
 })