new URLSearchParams(iterable)

• iterable <Iterable> 元素为键值对的可迭代对象

  ¥iterable <Iterable> An iterable object whose elements are key-value pairs

以类似于 <Map> 的构造函数的方式使用可迭代映射实例化新的 URLSearchParams 对象。iterable 可以是 Array 或任何可迭代对象。这意味着 iterable 可以是另一个 URLSearchParams，在这种情况下，构造函数将简单地创建提供的 URLSearchParams 的克隆。iterable 的元素是键值对，并且本身可以是任何可迭代对象。

¥Instantiate a new URLSearchParams object with an iterable map in a way that is similar to <Map>'s constructor. iterable can be an Array or any iterable object. That means iterable can be another URLSearchParams, in which case the constructor will simply create a clone of the provided URLSearchParams. Elements of iterable are key-value pairs, and can themselves be any iterable object.

允许重复的键。

¥Duplicate keys are allowed.

let params;

// Using an array
params = new URLSearchParams([
  ['user', 'abc'],
  ['query', 'first'],
  ['query', 'second'],
]);
console.log(params.toString());
// Prints 'user=abc&query=first&query=second'

// Using a Map object
const map = new Map();
map.set('user', 'abc');
map.set('query', 'xyz');
params = new URLSearchParams(map);
console.log(params.toString());
// Prints 'user=abc&query=xyz'

// Using a generator function
function* getQueryPairs() {
  yield ['user', 'abc'];
  yield ['query', 'first'];
  yield ['query', 'second'];
}
params = new URLSearchParams(getQueryPairs());
console.log(params.toString());
// Prints 'user=abc&query=first&query=second'

// Each key-value pair must have exactly two elements
new URLSearchParams([
  ['user', 'abc', 'error'],
]);
// Throws TypeError [ERR_INVALID_TUPLE]:
//        Each query pair must be an iterable [name, value] tuple 拷贝