编码

function encodeBase64(str: string): string {return btoa(encodeURIComponent(str).replace(/%([0-9A-F]{2})/g, function (match, p1) {return String.fromCharCode(parseInt(p1, 16))}))
}

解码

function decodeBase64(base64Str: string): string {return decodeURIComponent(atob(base64Str).split('').map(function (c) {return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)}).join(''))
}

npm库

https://www.npmjs.com/package/js-base64