diff --git a/components/NewSubgraph/NewSubgraph.tsx b/components/NewSubgraph/NewSubgraph.tsx
index dcd9b14..f7e443d 100644
--- a/components/NewSubgraph/NewSubgraph.tsx
+++ b/components/NewSubgraph/NewSubgraph.tsx
@@ -86,20 +86,21 @@ const ButtonsContainer = styled.div`
   }
 `
 
-export type ExtendedContract = Contract & { errorMessage?: string }
-
 const ADDRESS_REGEX = /^0x[0-9a-f]{40}$/i
+const MAPPING_FILENAME = 'mapping.ts'
+export type ExtendedContract = Contract & { errorMessage?: string }
 
 export const NewSubgraph = () => {
   const CHAIN_ID = '1'
 
   const [subgraphId, setSubgraphId] = useEditorState<string | null>('subgraph-file')
-  const { subgraph, saveContracts } = useLocalSubgraph(subgraphId)
+  const { subgraph, saveContracts, saveMapping } = useLocalSubgraph(subgraphId)
   const [contractAddress, setContractAddress] = useState('')
   const [started, setStarted] = useState(false)
   const [selectedContracts, setSelectedContracts] = useState<ExtendedContract[]>(
     subgraph?.contracts || []
   )
+
   const [mappingFunctionNames, setMappingFunctionNames] = useState<string[]>([])
   const router = useRouter()
   const [fnExtractionLoading, setFnExtractionLoading] = useState(false)
@@ -144,6 +145,12 @@ export const NewSubgraph = () => {
     }
   }, [subgraph?.mappings[DEFAULT_MAPPING]])
 
+  useEffect(() => {
+    if (subgraph?.contracts && !selectedContracts.length) {
+      setSelectedContracts(subgraph.contracts)
+    }
+  }, [subgraph])
+
   useEffect(() => {
     setStarted(true)
   }, [])
@@ -168,10 +175,28 @@ export const NewSubgraph = () => {
 
   const save = () => {
     let id = subgraphId
+    const newFnsToInsert: string[] = []
+    const contractsToSave = selectedContracts.map(sc => ({
+      ...sc,
+      events: sc.events.map((sce, i) => {
+        if (sce.handler === 'newFunction') {
+          const newFnName = `handle${sce.signature.split('(')[0]}${i}`
+          newFnsToInsert.push(`\nexport function ${newFnName}():void {}\n`)
+          return { ...sce, handler: newFnName }
+        }
+
+        return sce
+      }),
+    }))
+
     if (subgraph) {
-      saveContracts(selectedContracts)
+      saveMapping(
+        MAPPING_FILENAME,
+        subgraph.mappings[MAPPING_FILENAME].concat(newFnsToInsert.join('m'))
+      )
+      saveContracts(contractsToSave)
     } else {
-      id = newSubgraph({ contracts: selectedContracts })
+      id = newSubgraph({ contracts: contractsToSave })
     }
     setSubgraphId(id)
     router.push('/editor/subgraph')
diff --git a/components/NewSubgraph/SelectedContract.tsx b/components/NewSubgraph/SelectedContract.tsx
index 156c182..4e01dea 100644
--- a/components/NewSubgraph/SelectedContract.tsx
+++ b/components/NewSubgraph/SelectedContract.tsx
@@ -114,7 +114,7 @@ function parseEventsFromAbi(abi: any[]) {
     .map(
       e =>
         `${e.name}(${e.inputs
-          .map((ei: any) => `${ei.indexed ? 'indexed ' : ''}${ei.type}`)
+          .map((ei: any) => `${ei.indexed ? 'indexed ' : ''}${ei.type} ${ei.name}`)
           .join(', ')})`
     )
 }
@@ -135,11 +135,16 @@ export const SelectedContract = (props: SelectedContractProps) => {
     label: efa,
     value: efa,
   }))
-  const mappingFunctionsSelectOptions = mappingFunctionNames.map(mfn => ({
-    label: mfn,
-    value: mfn,
-  }))
-  const [eventHandlers, setEventHandlers] = useState<Event[]>([{ signature: '', handler: '' }])
+  const mappingFunctionsSelectOptions = [
+    { label: 'Create new handler', value: 'newFunction' },
+    ...mappingFunctionNames.map(mfn => ({
+      label: mfn,
+      value: mfn,
+    })),
+  ]
+  const [eventHandlers, setEventHandlers] = useState<Event[]>([
+    { signature: '', handler: 'newFunction' },
+  ])
 
   const fetchMetadata = async () => {
     const metadataReq = await fetch(`/api/etherscan/${addresses[CHAIN_ID]}/metadata`)
@@ -284,7 +289,9 @@ export const SelectedContract = (props: SelectedContractProps) => {
           fullWidth={false}
           variant="outline"
           className="new-event-handler-btn"
-          onClick={() => setEventHandlers(prev => [...prev, { signature: '', handler: '' }])}
+          onClick={() =>
+            setEventHandlers(prev => [...prev, { signature: '', handler: 'newFunction' }])
+          }
           {...(!contractHasEvents && { disabled: true, title: 'Contract has no events defined' })}>
           Add new event handler
         </Button>