在URL类中有一个内置函数，你可以使用它来轻松处理查询字符串的键/值参数:

const url = new URL(window.location.href);
// url.searchParams has several function, we just use `set` function
// to set a value, if you just want to append without replacing value
// let use `append` function

url.searchParams.set('key', 'value');

console.log(url.search) // <== '?key=value'

// if window.location.href has already some qs params this `set` function
// modify or append key/value in it

有关searchParams函数的更多信息。

IE不支持URL，请检查兼容性

你需要适应的基本实现是这样的:

function insertParam(key, value) {
    key = encodeURIComponent(key);
    value = encodeURIComponent(value);

    // kvp looks like ['key1=value1', 'key2=value2', ...]
    var kvp = document.location.search.substr(1).split('&');
    let i=0;

    for(; i<kvp.length; i++){
        if (kvp[i].startsWith(key + '=')) {
            let pair = kvp[i].split('=');
            pair[1] = value;
            kvp[i] = pair.join('=');
            break;
        }
    }

    if(i >= kvp.length){
        kvp[kvp.length] = [key,value].join('=');
    }

    // can return this or...
    let params = kvp.join('&');

    // reload page with new params
    document.location.search = params;
}

这大约是正则表达式或基于搜索的解决方案的两倍，但这完全取决于查询字符串的长度和任何匹配的索引

为了完成起见，我以慢速regex方法为基准(大约慢了150%)

function insertParam2(key,value)
{
    key = encodeURIComponent(key); value = encodeURIComponent(value);

    var s = document.location.search;
    var kvp = key+"="+value;

    var r = new RegExp("(&|\\?)"+key+"=[^\&]*");

    s = s.replace(r,"$1"+kvp);

    if(!RegExp.$1) {s += (s.length>0 ? '&' : '?') + kvp;};

    //again, do what you will here
    document.location.search = s;
}

这是一个非常简化的版本，为了可读性和更少的代码行而不是微观优化的性能(我们说的是几毫秒的差异，实际上……由于它的性质(操作当前文档的位置)，这将很可能在一个页面上运行一次)。

/**
* Add a URL parameter (or changing it if it already exists)
* @param {search} string  this is typically document.location.search
* @param {key}    string  the key to set
* @param {val}    string  value 
*/
var addUrlParam = function(search, key, val){
  var newParam = key + '=' + val,
      params = '?' + newParam;

  // If the "search" string exists, then build params from it
  if (search) {
    // Try to replace an existance instance
    params = search.replace(new RegExp('([?&])' + key + '[^&]*'), '$1' + newParam);

    // If nothing was replaced, then add the new param to the end
    if (params === search) {
      params += '&' + newParam;
    }
  }

  return params;
};

然后你可以这样使用:

document.location.pathname + addUrlParam(document.location.search, 'foo', 'bar');

就我所知，上面的答案都没有解决查询字符串包含参数的情况，这些参数本身就是一个数组，因此会出现不止一次，例如:

http://example.com?sizes[]=a&sizes[]=b

下面的函数是我用来更新document.location.search的。它接受一个键/值对数组作为参数，它将返回一个修改后的版本，你可以做任何你想做的事情。我是这样使用的:

var newParams = [
    ['test','123'],
    ['best','456'],
    ['sizes[]','XXL']
];
var newUrl = document.location.pathname + insertParams(newParams);
history.replaceState('', '', newUrl);

如果当前url为:

http://example.com/index.php?test=replaceme&sizes [] = XL

这会让你

http://example.com/index.php?test=123&sizes[]=XL&尺寸[]=XXL&best=456

函数

function insertParams(params) {
    var result;
    var ii = params.length;
    var queryString = document.location.search.substr(1);
    var kvps = queryString ? queryString.split('&') : [];
    var kvp;
    var skipParams = [];
    var i = kvps.length;
    while (i--) {
        kvp = kvps[i].split('=');
        if (kvp[0].slice(-2) != '[]') {
            var ii = params.length;
            while (ii--) {
                if (params[ii][0] == kvp[0]) {
                    kvp[1] = params[ii][1];
                    kvps[i] = kvp.join('=');
                    skipParams.push(ii);
                }
            }
        }
    }
    var ii = params.length;
    while (ii--) {
        if (skipParams.indexOf(ii) === -1) {
            kvps.push(params[ii].join('='));
        }
    }
    result = kvps.length ? '?' + kvps.join('&') : '';
    return result;
}

我会用这个小而完整的库来处理js中的url:

https://github.com/Mikhus/jsurl

我添加我的解决方案，因为它支持相对url除了绝对url。在其他方面，它与顶部的答案相同，后者也使用Web API。

/**
 * updates a relative or absolute
 * by setting the search query with
 * the passed key and value.
 */
export const setQueryParam = (url, key, value) => {
  const dummyBaseUrl = 'https://dummy-base-url.com';
  const result = new URL(url, dummyBaseUrl);
  result.searchParams.set(key, value);
  return result.toString().replace(dummyBaseUrl, '');
};

还有人开玩笑说:

// some jest tests
describe('setQueryParams', () => {
  it('sets param on relative url with base path', () => {
    // act
    const actual = setQueryParam(
      '/', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?ref=some-value');
  });
  it('sets param on relative url with no path', () => {
    // act
    const actual = setQueryParam(
      '', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?ref=some-value');
  });
  it('sets param on relative url with some path', () => {
    // act
    const actual = setQueryParam(
      '/some-path', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/some-path?ref=some-value');
  });
  it('overwrites existing param', () => {
    // act
    const actual = setQueryParam(
      '/?ref=prev-value', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?ref=some-value');
  });
  it('sets param while another param exists', () => {
    // act
    const actual = setQueryParam(
      '/?other-param=other-value', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?other-param=other-value&ref=some-value');
  });
  it('honors existing base url', () => {
    // act
    const actual = setQueryParam(
      'https://base.com', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('https://base.com/?ref=some-value');
  });
  it('honors existing base url with some path', () => {
    // act
    const actual = setQueryParam(
      'https://base.com/some-path', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('https://base.com/some-path?ref=some-value');
  });
});