How to add custom completions to language autocompletion list?

Hello,

I am setting language javascript() for Codemirror 6. I want to add a customCompletions to the JavaScript autocompletion list. Using override option shows me only customCompletions. But I want to see both language autocompletions and customCompletions. Which configuration option should I use?

const customCompletions = [
{ label: "Apple", type: "variable" },
{ label: "Banana", type: "variable" },
{ label: "Watermelon", type: "variable" }
];

this.view = new EditorView({
			doc: this.props.value,
			extensions: [
				basicSetup,
				javascript(),
				autocompletion({ override: customCompletions }) // TODO: don't override, add to JavaScript autocompletions
			],
			parent: this.editorRef.current
		});

See the autocompletion example.