node . js urlsearchparams API

哎哎哎:# t0]https://www . geeksforgeeks . org/node-js-urlsearchparams-API/

Node.js 是一个开源项目，广泛用于动态 web 应用程序的开发。Node.js 中的 URLSearchParams API 允许对 URL 查询进行读写操作。

URLSearchParams 类是一个全局对象，与以下四个构造函数之一一起使用。

施工人员:

1. 新的 URLSearchParams(): 无参数构造函数实例化新的空 URLSearchParams 对象。

2. new URLSearchParams(string): Accepts a string as an argument to instantiate a new URLSearchParams object.

   js var params = new URLSearchParams('user=abc&q=xyz'); console.log(params.get('user')); console.log(params.get('q'));

   输出:

   js abc xyz

3. new URLSearchParams(obj): Accepts an object with a collection of key-value pairs to instantiate a new URLSearchParams object. The key-value pair of obj are always coerced to strings. Duplicate keys are not allowed.

   js const params = new URLSearchParams({   user: 'ana',   course: ['math', 'chem', 'phys'] }); console.log(params.toString());

   输出:

   js user=ana&course=math%2Cchem%2Cphys

4. new URLSearchParams(iterable): Accepts an iterable object having a collection of key-value pairs to instantiate a new URLSearchParams object. Iterable can be any iterable object. Since URLSearchParams is iterable, an iterable object can be another URLSearchParams, where the constructor will create a clone of the provided URLSearchParams. Duplicate keys are allowed.

   js // Using a Map object as it is iterable const map = new Map(); map.set('West Bengal', 'Kolkata'); map.set('Karnataka', 'Bengaluru'); params = new URLSearchParams(map); console.log(params.toString());

   输出:

   js West+Bengal=Kolkata&Karnataka=Bengaluru

访问网址查询:

• urlSearchParams.get(name): Returns the value of the first name-value pair that matches with the argument passed. If no such pair exists, null is returned.

  ```js const myURL = new URL(   'https://example.org/?abc=123&abc=526');

  console.log(myURL.searchParams.get('abc')); ```

  输出:

  js 123

• urlSearchParams.getAll(name): Returns all the value of the name-value pair that matches with the argument passed. If no such pair exists, null is returned.

  js const myURL = new URL(   'https://example.org/?abc=123&abc=526'); console.log(myURL.searchParams.getAll('abc'));

  输出:

  js [ '123', '526' ]

• urlSearchParams.has(name): Returns true if the argument passed matches with any existing name of the name-value pair else returns false.

  js const myURL = new URL(   'https://example.org/?abc=123&xyz=526'); console.log(myURL.searchParams.has('abc')); console.log(myURL.searchParams.has('pqr'));

  输出:

  js true false

操纵网址查询:

• urlSearchParams.set(name, value): Sets the value in the URLSearchParams object associated with name to the specified value. If more than one name-value pairs exists, whose names are same as the ‘name’ argument, then the only value of first matching pair is changed, rest all are removed.

  js const params = new URLSearchParams(     'abc=123&xyz=526&abc=258'); console.log(params.toString()); params.set('abc', 'opq'); console.log(params.toString());

  输出:

  js abc=123&xyz=526&abc=258 abc=opq&xyz=526

• urlSearchParams.append(name, value): Appends a new name-value pair to the existing URLSearchParams query.

  js const params = new URLSearchParams('xyz=123'); params.append('foo', '789'); params.append('xyz', 'zoo'); params.append('foo', 'def'); console.log(params.toString());

  输出:

  js xyz=123&foo=789&xyz=zoo&foo=def

• urlSearchParams.delete(name): Removes all name-value pairs whose name is same as ‘name’ argument.

  js const params = new URLSearchParams(   'xyz=123&foo=789&xyz=zoo&foo=def'); console.log(params.toString()); params.delete('foo'); console.log(params.toString());

  输出:

  js xyz=123&foo=789&xyz=zoo&foo=def xyz=123&xyz=zoo

• urlSearchParams.sort(): Sorts the existing name-value pairs in-place by their names using a stable sorting algorithm.

  js const params = new URLSearchParams(   'query=node&type=search&abc=programs'); params.sort(); console.log(params.toString());

  输出:

  js abc=programs&query=node&type=search

• urlSearchParams.toString(): Returns the URL search parameters as a string, with characters percent-encoded wherever necessary.

  js const params = new URLSearchParams(   'query=node&type=search&passwd[]=3456'); console.log(params.toString());

  输出:

  js query=node&type=search&passwd%5B%5D=3456

迭代网址查询:

• urlSearchParams.entries(): Returns an iterator over the entry set of the param object.

  js const params = new URLSearchParams(     'query=node&type=search&passwd=3456'); for(var pair of params.entries()) {    console.log(pair[0]+ '-->'+ pair[1]);  }

  输出:

  js query-->node type-->search passwd-->3456

• urlSearchParams.keys(): Returns an iterator over the key set of the param object.

  js const params = new URLSearchParams(     'query=node&type=search&passwd=3456'); for(var key of params.keys()) {    console.log(key);  }

  输出:

  js query type passwd

• urlSearchParams.values(): Returns an iterator over the value set of the param object.

  js const params = new URLSearchParams(     'query=node&type=search&passwd=3456'); for(var value of params.values()) {    console.log(value);  }

  输出:

  js node search 3456

• urlSearchParams.forEach(fn[, arg]): fn is a function invoked for each name-value pair in the query and arg is an object to be used when ‘fn’ is called. It iterates over each name-value pair in the query and invokes the function.

  js const myURL = new URL(   'https://example.com/?a=b&c=d&d=z'); myURL.searchParams.forEach(   (value, name, searchParams) => { console.log(name, value,    myURL.searchParams === searchParams); });

  输出:

  js a b true c d true d z true

• urlSearchParamsSymbol.iterator:

  js const params=new URLSearchParams(     'firstname=john&lastname=beck&gender=male'); for (const [name, value] of params) {   console.log(name, value); }

  输出:

  ```js firstname john lastname beck gender male

  ```

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