convert search component to typescript

packages/bbui/src/Form/Search.svelte

@@ -1,20 +1,20 @@
-<script>
+<script lang="ts">
   import Field from "./Field.svelte"
   import Search from "./Core/Search.svelte"
   import { createEventDispatcher } from "svelte"
 
-  export let value = null
-  export let label = null
-  export let labelPosition = "above"
-  export let placeholder = null
+  export let value: string | undefined = undefined
+  export let label: string | undefined = undefined
+  export let labelPosition: "above" | "below" = "above"
+  export let placeholder: string | undefined = undefined
   export let disabled = false
   export let updateOnChange = true
   export let quiet = false
-  export let inputRef = undefined
-  export let helpText = null
+  export let inputRef: HTMLInputElement | undefined = undefined
+  export let helpText: string | undefined = undefined
 
   const dispatch = createEventDispatcher()
-  const onChange = e => {
+  const onChange = (e: CustomEvent<string>) => {
     value = e.detail
     dispatch("change", e.detail)
   }