export function char2fileName(char: string): string { let codes = Array.from(char) .map(x => x.codePointAt(0)?.toString(16)) .filter((x: T | undefined): x is T => x !== undefined); if (!codes.includes('200d')) codes = codes.filter(x => x !== 'fe0f'); codes = codes.filter(x => x.length !== 0); return codes.join('-'); }