chinese-parseint2/src/index.ts

parse Chinese numeric strings to integer

import { characters } from './data';
export { characters } from './data';

export function _isNegative(str: string)
{
	return /^[負负-]/.test(str)
}

export function isSpecialCharVal(char: string | keyof typeof characters): char is keyof typeof characters
{
	return typeof getSpecialCharVal(char) === 'number'
}

export function getSpecialCharVal(char: string | keyof typeof characters)
{
	return characters[char as keyof typeof characters]
}

export function chinese_parseInt(str: string, radix?: number)
{
	const result = parseInt(str, radix);
	if (!isNaN(result)) return result;
	if (typeof str !== "string") return NaN;

	str = str.replace(/[\s　]+/g, "");

	return _chineseParseIntCore(str);
}

export function _chineseParseIntCore(str: string)
{
	const negative = _isNegative(str);
	if (negative) str = str.slice(1);

	let charVal: number;
	let result = 0;
	/**
	 * 不到一萬的部分
	 */
	let partialSum = 0; ///< 不到一萬的部分
	/**
	 * 個位數，預設為 -1 以區分有無"零"的出現
	 */
	let digit = -1;

	for (let i = 0; i < str.length; ++i)
	{
		charVal = getSpecialCharVal(str.charAt(i)); ///< 暫存字元代表的數值
		if (charVal === undefined) return NaN; // 有任何不認得的字，直接 NaN
		if (charVal < 10)
		{
			digit = (digit == -1)
				? charVal
				: digit * 10 + charVal  // ex. 零五、二五六萬
			;
		}
		else if (charVal < 1e+4)
		{
			if (digit == -1) digit = 1;
			if (i > 1 && digit == 0 && getSpecialCharVal(str.charAt(i - 2)) != 100)
			{
				digit = 1;
			} // 處理"一千零十一"；搜尋"千零十"的確是出現過的。
			partialSum += digit * charVal;
			digit = -1;
		}
		else
		{
			if (digit != -1) partialSum += digit;
			if (i && getSpecialCharVal(str.charAt(i - 1)) >= 1e+4) // 為了"四萬萬五千萬"
			{
				result *= getSpecialCharVal(str.charAt(i));
			}
			else
			{
				result += partialSum * charVal;
			}
			partialSum = 0;
			digit = -1;
		}
	}
	if (digit > 0)
	{
		if (str.length > 1)
		{
			// 為了處理"二十四萬二"、"二百五"等
			charVal = getSpecialCharVal(str.charAt(str.length - 2));
			if (charVal < 100)
			{
				partialSum += digit;
			}
			else
			{
				charVal /= charVal.toString().charAt(0) as any;  // 把「皕」轉成100
				partialSum += digit * (charVal / 10);
			}
		}
		else
		{
			partialSum += digit;
		}
	}
	result += partialSum;

	if (negative) result *= -1;

	return result;
}

export default chinese_parseInt