Add join to funcNames, and use to build declerationFunctions

ui/src/ifql/components/BodyBuilder.tsx

@@ -74,9 +74,9 @@ class BodyBuilder extends PureComponent<Props> {
 
   private get newDeclarationFuncs(): string[] {
     const {body} = this.props
-    const declarationFunctions = ['from']
+    const declarationFunctions = [funcNames.FROM]
     if (body.length > 1) {
-      declarationFunctions.push('join')
+      declarationFunctions.push(funcNames.JOIN)
     }
     return declarationFunctions
   }
@@ -85,6 +85,9 @@ class BodyBuilder extends PureComponent<Props> {
     if (name === funcNames.FROM) {
       this.props.onAppendFrom()
     }
+    if (name === funcNames.JOIN) {
+      this.props.onAppendJoin()
+    }
   }
 
   private get funcNames() {

ui/src/ifql/constants/funcNames.ts

@@ -1,2 +1,3 @@
 export const FROM = 'from'
 export const FILTER = 'filter'
+export const JOIN = 'join'