export function isAbbreviationValid()

in src/emmetHelper.ts [486:520]

• 30 lines of code
• 16 McCabe index (conditional complexity)

export function isAbbreviationValid(syntax: string, abbreviation: string): boolean {
	if (!abbreviation) {
		return false;
	}
	if (isStyleSheet(syntax)) {
		if (abbreviation.includes('#')) {
			if (abbreviation.startsWith('#')) {
				const hexColorRegex = /^#[\d,a-f,A-F]{1,6}$/;
				return hexColorRegex.test(abbreviation);
			} else if (commonlyUsedTags.includes(abbreviation.substring(0, abbreviation.indexOf('#')))) {
				return false;
			}
		}
		return cssAbbreviationRegex.test(abbreviation);
	}
	if (abbreviation.startsWith('!')) {
		return !/[^!]/.test(abbreviation);
	}

	// Its common for users to type (sometextinsidebrackets), this should not be treated as an abbreviation
	// Grouping in abbreviation is valid only if it's inside a text node or preceeded/succeeded with one of the symbols for nesting, sibling, repeater or climb up
	// Also, cases such as `span[onclick="alert();"]` are valid
	if ((/\(/.test(abbreviation) || /\)/.test(abbreviation))
		&& !/\{[^\}\{]*[\(\)]+[^\}\{]*\}(?:[>\+\*\^]|$)/.test(abbreviation)
		&& !/\(.*\)[>\+\*\^]/.test(abbreviation)
		&& !/\[[^\[\]\(\)]+=".*"\]/.test(abbreviation)
		&& !/[>\+\*\^]\(.*\)/.test(abbreviation)) {
		return false;
	}

	if (syntax === 'jsx') {
		return (jsxAbbreviationStartRegex.test(abbreviation) && htmlAbbreviationRegex.test(abbreviation));
	}
	return (htmlAbbreviationStartRegex.test(abbreviation) && htmlAbbreviationRegex.test(abbreviation));
}