Restructure and rename components

src/libs/style.js

@@ -0,0 +1,78 @@
+import React from 'react';
+import Immutable from 'immutable'
+import spec from 'mapbox-gl-style-spec/reference/latest.min.js'
+import diffJSONStyles from 'mapbox-gl-style-spec/lib/diff'
+
+// Standard JSON to Immutable conversion except layers
+// are stored in an OrderedMap to make lookups id fast
+// It also ensures that every style has an id and
+// a created date for future reference
+function fromJSON(jsonStyle) {
+  if (typeof jsonStyle === 'string' || jsonStyle instanceof String) {
+    jsonStyle = JSON.parse(jsonStyle)
+  }
+
+  return Immutable.Map(Object.keys(jsonStyle).map(key => {
+    const val = jsonStyle[key]
+    if(key === "layers") {
+      return [key, Immutable.OrderedMap(val.map(l => [l.id, Immutable.fromJS(l)]))]
+    } else if(key === "sources" || key === "metadata" || key === "transition") {
+      return [key, Immutable.fromJS(val)]
+    } else {
+      return [key, val]
+    }
+  }))
+}
+
+// Empty style is always used if no style could be restored or fetched
+const emptyStyle = ensureMetadataExists(fromJSON({
+  version: 8,
+  sources: {},
+  layers: [],
+}))
+
+function ensureHasId(style) {
+  if(style.has('id')) return style
+  return style.set('id', Math.random().toString(36).substr(2, 9))
+}
+
+function ensureHasTimestamp(style) {
+  if(style.has('id')) return style
+  return style.set('created', new Date().toJSON())
+}
+
+function ensureMetadataExists(style) {
+  return ensureHasId(ensureHasTimestamp(style))
+}
+
+// Compare style with other style and return changes
+//TODO: Write own diff algo that operates on immutable collections
+// Should be able to improve performance since we can only compare
+// by reference
+function diffStyles(before, after) {
+  return diffJSONStyles(toJSON(before), toJSON(after))
+}
+
+// Turns immutable style back into JSON with the original order of the
+// layers preserved
+function toJSON(mapStyle) {
+  const jsonStyle = {}
+  for(let [key, value] of mapStyle.entries()) {
+    if(key === "layers") {
+      jsonStyle[key] = value.toIndexedSeq().toJS()
+    } else if(key === 'sources' || key === "metadata" || key === "transition") {
+      jsonStyle[key] = value.toJS()
+    } else {
+      jsonStyle[key] = value
+    }
+  }
+  return jsonStyle
+}
+
+export default {
+  toJSON,
+  fromJSON,
+  diffStyles,
+  ensureMetadataExists,
+  emptyStyle,
+}