[aggParams/field] support aggParamType#scriptable

Author: spalger

src/ui/public/agg_types/buckets/significant_terms.js

@@ -16,6 +16,7 @@ export default function SignificantTermsAggDefinition(Private) {
     params: [
       {
         name: 'field',
+        scriptable: false,
         filterFieldTypes: 'string'
       },
       {

src/ui/public/agg_types/buckets/terms.js

@@ -43,7 +43,6 @@ export default function TermsAggDefinition(Private) {
     params: [
       {
         name: 'field',
-        scriptable: true,
         filterFieldTypes: ['number', 'boolean', 'date', 'ip',  'string']
       },
       {

src/ui/public/agg_types/param_types/field.js

@@ -14,7 +14,7 @@ export default function FieldAggParamFactory(Private, $filter) {
   }
 
   FieldAggParam.prototype.editor = editorHtml;
-  FieldAggParam.prototype.scriptable = false;
+  FieldAggParam.prototype.scriptable = true;
   FieldAggParam.prototype.filterFieldTypes = '*';
 
   /**
@@ -36,6 +36,10 @@ export default function FieldAggParamFactory(Private, $filter) {
 
     fields = fields.filter(f => f.aggregatable);
 
+    if (!this.scriptable) {
+      fields = fields.filter(field => !field.scripted);
+    }
+
     if (this.filterFieldTypes) {
       fields = $filter('fieldType')(fields, this.filterFieldTypes);
     }