ohpm install 之后的使用

/** 
 * Calculates the byte length of a base64 encoded string. 
 * @param {string} string Base64 encoded string 
 * @returns {number} Byte length 
 */ 
export function length(string: string): number; 
 
/** 
 * Encodes a buffer to a base64 encoded string. 
 * @param {Uint8Array} buffer Source buffer 
 * @param {number} start Source start 
 * @param {number} end Source end 
 * @returns {string} Base64 encoded string 
 */ 
export function encode(buffer: Uint8Array, start: number, end: number): string; 
 
/** 
 * Decodes a base64 encoded string to a buffer. 
 * @param {string} string Source string 
 * @param {Uint8Array} buffer Destination buffer 
 * @param {number} offset Destination offset 
 * @returns {number} Number of bytes written 
 * @throws {Error} If encoding is invalid 
 */ 
export function decode(string: string, buffer: Uint8Array, offset: number): number; 
 
/** 
 * Tests if the specified string appears to be base64 encoded. 
 * @param {string} string String to test 
 * @returns {boolean} `true` if it appears to be base64 encoded, otherwise false 
 */ 
export function test(string: string): boolean;