Uncaught TypeError: Cannot read property 'slice' of null

[ikafie]

What happened:
I have one problem 'slice' of null in my project. It's an Angular project.

More info:
It was working well before when my project was running under Angular v7. This issue did happen after updating to Angular v10.

Error message:
Uncaught TypeError: Cannot read property 'slice' of null
at parseJSFunc (quirc.js:421)

var sourceRegex = /^function\s*\(([^)]*)\)\s*{\s*([^*]*?)[\s;]*(?:return\s*(.*?)[;\s]*)?}$/;
			function parseJSFunc(jsfunc) {
				var parsed = jsfunc.toString().match(sourceRegex).slice(1);
				return {
					arguments: parsed[0],
					body: parsed[1],
					returnValue: parsed[2]
		}
}