Avoid usage of logical nullish assignment for node 14 compatibility

src/system/keyboard.ts

@@ -98,7 +98,7 @@ export class KeyboardHost {
     const target = getActiveElementOrBody(config.document)
     this.setKeydownTarget(target)
 
-    this.pressed[code] ??= {
+    this.pressed[code] = this.pressed[code] ?? {
       keyDef,
       unpreventedDefault: false,
     }

src/system/pointer/index.ts

@@ -41,7 +41,7 @@ export class PointerHost {
     private registry = {} as Record<string, Device>
 
     get(k: string) {
-      this.registry[k] ??= new Device()
+      this.registry[k] = this.registry[k] ?? new Device()
       return this.registry[k]
     }
   })()

src/utils/misc/level.ts

@@ -16,7 +16,7 @@ declare module '../../setup' {
 }
 
 export function setLevelRef(config: Config, level: ApiLevel) {
-  config[Level] ??= {}
+  config[Level] = config[Level] ?? {}
   config[Level][level] = {}
 }