 class MyURLSearchParams {   /**    * @params {string} init    */   array   constructor(init) {     this.array = [];     init = init[0] === '?' ? init.slice(1) : init;     const arr = init.split('&');     arr.forEach(item => {       this.array.push([item.split('=')[0], item.split('=')[1]]);     })   }      /**     * @params {string} name    * @params {any} value    */   append(name, value) {     this.array.push([name, '' + value])   }      /**    * @params {string} name    */   delete(name) {    let index = this.array.findIndex(item => item[0] === name)    while(index>=0) {      this.array.splice(index, 1);      index = this.array.findIndex(item => item[0] === name)    }   }      /**    * @returns {Iterator}     */   *entries() {      for(let i=0; i<this.array.length; i++) {          yield [this.array[i][0],this.array[i][1]]      }   }      /**    * @param {(value, key) => void} callback    */   forEach(callback) {    this.array.forEach((item)=>{      callback.apply(this,[item[1], item[0]])    })   }      /**    * @param {string} name    * returns the first value of the name    */   get(name) {     const index = this.array.findIndex(item => item[0] === name)     return index > -1 ?  this.array[index][1] :  null   }      /**    * @param {string} name    * @return {string[]}    * returns the value list of the name    */   getAll(name) {     const all = []     this.array.forEach(item =>{       if(item[0] === name) {         all.push(item[1])       }     })     return all   }      /**    * @params {string} name    * @return {boolean}    */   has(name) {     return this.array.findIndex(item => item[0] === name) >= 0;   }      /**    * @return {Iterator}    */   keys() {     return this.array.map(item => item[0])   }      /**    * @param {string} name    * @param {any} value    */   set(name, value) {    const index = this.array.findIndex(item => item[0] === name)    this.delete(name);    this.array.splice(index, 0, [name, '' + value]);   }      // sor all key/value pairs based on the keys   sort() {    this.array.sort((item1, item2)=>{     if(item1[0] > item2[0]) {       return 1     } else {       return -1     }    })   }      /**    * @return {string}    */   toString() {    const results = this.array.map((item)=>{      return `${item[0]}=${item[1]}`    })    return results.join('&');   }      /**    * @return {Iterator} values    */   values() {   return this.array.map(item => item[1])   } }const params = new MyURLSearchParams('?a=1&a=1&a=2&b=2')const entries = params.entries()console.log(params.entries().next())