tax-invoice/dist/utils.js

发票SDK-提供完整的发票API开票接口

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.Utils = void 0;
const crypto_1 = __importDefault(require("crypto"));
const decimal_js_1 = require("decimal.js");
/**
 * 工具类 - 提供签名、随机字符串等通用功能
 */
class Utils {
    /**
     * 生成随机字符串
     * @param length 字符串长度，默认20
     * @returns 随机字符串
     */
    static generateRandomString(length = 20) {
        const characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
        let randomString = '';
        for (let i = 0; i < length; i++) {
            randomString += characters.charAt(Math.floor(Math.random() * characters.length));
        }
        return randomString;
    }
    /**
     * 获取当前时间戳（秒）
     * @returns 时间戳字符串
     */
    static getTimestamp() {
        return Math.floor(Date.now() / 1000).toString();
    }
    /**
     * 计算签名
     * @param method HTTP方法
     * @param path 请求路径
     * @param randomString 随机字符串
     * @param timestamp 时间戳
     * @param appKey 应用密钥
     * @param appSecret 应用密钥
     * @returns 签名
     */
    static calculateSignature(method, path, randomString, timestamp, appKey, appSecret) {
        // 构建签名字符串
        const signContent = `Method=${method}&Path=${path}&RandomString=${randomString}&TimeStamp=${timestamp}&AppKey=${appKey}`;
        // 使用HMAC-SHA256计算签名
        const hmac = crypto_1.default.createHmac('sha256', appSecret);
        hmac.update(signContent);
        const signature = hmac.digest('hex');
        // 转为大写
        return signature.toUpperCase();
    }
    /**
     * 计算税额
     * @param amount 金额
     * @param taxRate 税率
     * @param isIncludeTax 是否含税，默认为false
     * @param scale 小数位数，默认2位
     * @returns 税额
     */
    static calculateTax(amount, taxRate, isIncludeTax = false, scale = 2) {
        const amountDecimal = new decimal_js_1.Decimal(amount);
        const taxRateDecimal = new decimal_js_1.Decimal(taxRate);
        const oneDecimal = new decimal_js_1.Decimal(1);
        let tax;
        if (isIncludeTax) {
            //旧 含税计算：税额 = 金额 / (1 + 税率) * 税率
            // tax = amountDecimal.div(taxRateDecimal.add(1)).mul(taxRateDecimal);
            //新 含税计算：税额 = 1 / (1 + 税率) * 税率 * 含税金额
            tax = oneDecimal.div(oneDecimal.add(taxRateDecimal)).mul(taxRateDecimal).mul(amountDecimal);
        }
        else {
            // 不含税计算：税额 = 金额 * 税率
            tax = amountDecimal.mul(taxRateDecimal);
        }
        return tax.toFixed(scale);
    }
}
exports.Utils = Utils;