Switch from exclamation point to declare syntax for type-only properties

Author: marijnh

src/blockview.ts

@@ -16,11 +16,11 @@ export interface BlockView extends ContentView {
 export class LineView extends ContentView implements BlockView {
   children: ContentView[] = []
   length: number = 0
-  dom!: HTMLElement | null
+  declare dom: HTMLElement | null
   prevAttrs: Attrs | null | undefined = undefined
   attrs: Attrs | null = null
   breakAfter = 0
-  parent!: DocView | null
+  declare parent: DocView | null
 
   // Consumes source
   merge(from: number, to: number, source: BlockView | null, hasStart: boolean, openStart: number, openEnd: number): boolean {
@@ -172,8 +172,8 @@ export class LineView extends ContentView implements BlockView {
 }
 
 export class BlockWidgetView extends ContentView implements BlockView {
-  dom!: HTMLElement | null
-  parent!: DocView | null
+  declare dom: HTMLElement | null
+  declare parent: DocView | null
   breakAfter = 0
   prevWidget: WidgetType | null = null
 

src/contentview.ts

@@ -32,7 +32,7 @@ export abstract class ContentView {
   flags: number = ViewFlag.NodeDirty
   abstract length: number
   abstract children: ContentView[]
-  breakAfter!: number
+  declare breakAfter: number
 
   get overrideDOMText(): Text | null { return null }
 

src/decoration.ts

@@ -214,7 +214,7 @@ export abstract class Decoration extends RangeValue {
     readonly spec: any) { super() }
 
   /// @internal
-  point!: boolean
+  declare point: boolean
 
   /// @internal
   get heightRelevant() { return false }

src/docview.ts

@@ -22,7 +22,7 @@ type Composition = {
 }
 
 export class DocView extends ContentView {
-  children!: BlockView[]
+  declare children: BlockView[]
 
   decorations: readonly DecorationSet[] = []
   dynamicDecorationMap: boolean[] = [false]
@@ -49,7 +49,7 @@ export class DocView extends ContentView {
   impreciseHead: DOMPos | null = null
   forceSelection = false
 
-  dom!: HTMLElement
+  declare dom: HTMLElement
 
   // Used by the resize observer to ignore resizes that we caused
   // ourselves
@@ -572,7 +572,7 @@ export class DocView extends ContentView {
   }
 
   // Will never be called but needs to be present
-  split!: () => ContentView
+  declare split: () => ContentView
 }
 
 function betweenUneditable(pos: DOMPos) {

src/editorview.ts

@@ -145,7 +145,7 @@ export class EditorView {
   private announceDOM: HTMLElement
 
   /// @internal
-  inputState!: InputState
+  declare inputState: InputState
 
   /// @internal
   public viewState: ViewState
@@ -156,7 +156,7 @@ export class EditorView {
   private pluginMap: Map<ViewPlugin<any>, PluginInstance | null> = new Map
   private editorAttrs: Attrs = {}
   private contentAttrs: Attrs = {}
-  private styleModules!: readonly StyleModule[]
+  declare private styleModules: readonly StyleModule[]
   private bidiCache: CachedOrder[] = []
 
   private destroyed = false;

src/gutter.ts

@@ -23,7 +23,7 @@ export abstract class GutterMarker extends RangeValue {
 
   /// This property can be used to add CSS classes to the gutter
   /// element that contains this marker.
-  elementClass!: string
+  declare elementClass: string
 
   /// Called if the marker has a `toDOM` method and its representation
   /// was removed from a gutter.

src/heightmap.ts

@@ -149,7 +149,7 @@ export abstract class HeightMap {
     public flags: number = Flag.Outdated
   ) {}
 
-  size!: number
+  declare size: number
 
   get outdated() { return (this.flags & Flag.Outdated) > 0 }
   set outdated(value) { this.flags = (value ? Flag.Outdated : 0) | (this.flags & ~Flag.Outdated) }

src/inlineview.ts

@@ -9,8 +9,8 @@ import {EditorView} from "./editorview"
 const MaxJoinLen = 256
 
 export class TextView extends ContentView {
-  children!: ContentView[]
-  dom!: Text | null
+  declare children: ContentView[]
+  declare dom: Text | null
 
   constructor(public text: string) {
     super()
@@ -69,7 +69,7 @@ export class TextView extends ContentView {
 }
 
 export class MarkView extends ContentView {
-  dom!: HTMLElement | null
+  declare dom: HTMLElement | null
 
   constructor(readonly mark: MarkDecoration,
               public children: ContentView[] = [],
@@ -159,8 +159,8 @@ function textCoords(text: Text, pos: number, side: number): Rect | null {
 
 // Also used for collapsed ranges that don't have a placeholder widget!
 export class WidgetView extends ContentView {
-  children!: ContentView[]
-  dom!: HTMLElement | null
+  declare children: ContentView[]
+  declare dom: HTMLElement | null
   prevWidget: WidgetType | null = null
 
   static create(widget: WidgetType, length: number, side: number) {
@@ -256,8 +256,8 @@ export class WidgetView extends ContentView {
 // browser bugs that show up when the cursor is directly next to
 // uneditable inline content.
 export class WidgetBufferView extends ContentView {
-  children!: ContentView[]
-  dom!: HTMLElement | null
+  declare children: ContentView[]
+  declare dom: HTMLElement | null
 
   constructor(readonly side: number) { super() }
 

src/placeholder.ts

@@ -48,7 +48,7 @@ export function placeholder(content: string | HTMLElement | ((view: EditorView)
         : Decoration.none
     }
 
-    update!: () => void // Kludge to convince TypeScript that this is a plugin value
+    declare update: () => void // Kludge to convince TypeScript that this is a plugin value
 
     get decorations() { return this.view.state.doc.length ? Decoration.none : this.placeholder }
   }, {decorations: v => v.decorations})

src/tooltip.ts

@@ -141,7 +141,7 @@ const tooltipPlugin = ViewPlugin.fromClass(class {
   position: "fixed" | "absolute"
   madeAbsolute = false
   parent: HTMLElement | null
-  container!: HTMLElement
+  declare container: HTMLElement
   classes: string
   intersectionObserver: IntersectionObserver | null
   resizeObserver: ResizeObserver | null