/*
 ** Core logic from https://github.com/component/escape-html
 ** Many thanks to @component
 */

const matchHtmlRegExp = /["'&<>]/

export const escapeHTML = (string?: string | null): string => {
	const str = "" + string
	const match = matchHtmlRegExp.exec(str)

	if (!match) {
		return str
	}

	let escape
	let html = ""
	let index = 0
	let lastIndex = 0

	for (index = match.index; index < str.length; index++) {
		switch (str.charCodeAt(index)) {
			case 34: // "
				escape = "&quot;"
				break
			case 38: // &
				escape = "&amp;"
				break
			case 39: // '
				escape = "&#39;"
				break
			case 60: // <
				escape = "&lt;"
				break
			case 62: // >
				escape = "&gt;"
				break
			default:
				continue
		}

		if (lastIndex !== index) {
			html += str.substring(lastIndex, index)
		}

		lastIndex = index + 1
		html += escape
	}

	return lastIndex !== index ? html + str.substring(lastIndex, index) : html
}