rudeshark.net/packages/megalodon/src/cancel.ts

export class RequestCanceledError extends Error {
	public isCancel: boolean;

	constructor(msg: string) {
		super(msg);
		this.isCancel = true;
		Object.setPrototypeOf(this, RequestCanceledError);
	}
}

export const isCancel = (value: any): boolean => {
	return value && value.isCancel;
};