base64的字符串简单加密，主用于网页缓存数据的加密。

适用于常规html、小游戏（egret、cocos、laya）等

原文参考：JS基于base64编码加密解密文本和图片（修订）_js base64加密-CSDN博客

测试：JS实现base64加密解密的方法 - web开发 - 亿速云

export class Base64 {private static _keyStr: string = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";/**字符串加密*/public static encode(e) {var t = "";var n, r, i, s, o, u, a;var f = 0;e = Base64._utf8_encode(e);while (f < e.length) {n = e.charCodeAt(f++);r = e.charCodeAt(f++);i = e.charCodeAt(f++);s = n >> 2;o = (n & 3) << 4 | r >> 4;u = (r & 15) << 2 | i >> 6;a = i & 63;if (isNaN(r)) {u = a = 64} else if (isNaN(i)) {a = 64}t = t + this._keyStr.charAt(s) + this._keyStr.charAt(o) + this._keyStr.charAt(u) + this._keyStr.charAt(a)}return t}/**字符串解密*/public static decode(e) {var t = "";var n, r, i;var s, o, u, a;var f = 0;e = e.replace(/[^A-Za-z0-9+/=]/g, "");while (f < e.length) {s = this._keyStr.indexOf(e.charAt(f++));o = this._keyStr.indexOf(e.charAt(f++));u = this._keyStr.indexOf(e.charAt(f++));a = this._keyStr.indexOf(e.charAt(f++));n = s << 2 | o >> 4;r = (o & 15) << 4 | u >> 2;i = (u & 3) << 6 | a;t = t + String.fromCharCode(n);if (u != 64) {t = t + String.fromCharCode(r)}if (a != 64) {t = t + String.fromCharCode(i)}}t = Base64._utf8_decode(t);return t}private static _utf8_encode(e) {e = e.replace(/rn/g, "n");var t = "";for (var n = 0; n < e.length; n++) {var r = e.charCodeAt(n);if (r < 128) {t += String.fromCharCode(r)} else if (r > 127 && r < 2048) {t += String.fromCharCode(r >> 6 | 192);t += String.fromCharCode(r & 63 | 128)} else {t += String.fromCharCode(r >> 12 | 224);t += String.fromCharCode(r >> 6 & 63 | 128);t += String.fromCharCode(r & 63 | 128)}}return t}private static _utf8_decode(e) {let t = "";let n = 0;let r = 0;let c1 = 0;let c2 = 0;let c3 = 0;while (n < e.length) {r = e.charCodeAt(n);if (r < 128) {t += String.fromCharCode(r);n++} else if (r > 191 && r < 224) {c2 = e.charCodeAt(n + 1);t += String.fromCharCode((r & 31) << 6 | c2 & 63);n += 2} else {c2 = e.charCodeAt(n + 1);c3 = e.charCodeAt(n + 2);t += String.fromCharCode((r & 15) << 12 | (c2 & 63) << 6 | c3 & 63);n += 3}}return t}
}

使用方法：

    const num = Base64.encode(this.editBox.string);Log.log("jia mi:", num)const num = Base64.decode(this.editBox.string);Log.log("解密:", num)