|                                                                |  | 'use strict'
import * as utils from './../utils'
function encode(val) {  return encodeURIComponent(val).replace(/%40/gi, '@').replace(/%3A/gi, ':').replace(/%24/g, '$').replace(/%2C/gi, ',').replace(/%20/g, '+').replace(/%5B/gi, '[').replace(/%5D/gi, ']')}
/** * Build a URL by appending params to the end * * @param {string} url The base of the url (e.g., http://www.google.com)
 * @param {object} [params] The params to be appended * @returns {string} The formatted url */export default function buildURL(url, params, paramsSerializer) {  /*eslint no-param-reassign:0*/  if (!params) {    return url  }
  var serializedParams  if (paramsSerializer) {    serializedParams = paramsSerializer(params)  } else if (utils.isURLSearchParams(params)) {    serializedParams = params.toString()  } else {    var parts = []
    utils.forEach(params, function serialize(val, key) {      if (val === null || typeof val === 'undefined') {        return      }
      if (utils.isArray(val)) {        key = key + '[]'      } else {        val = [val]      }
      utils.forEach(val, function parseValue(v) {        if (utils.isDate(v)) {          v = v.toISOString()        } else if (utils.isObject(v)) {          v = JSON.stringify(v)        }        parts.push(encode(key) + '=' + encode(v))      })    })
    serializedParams = parts.join('&')  }
  if (serializedParams) {    var hashmarkIndex = url.indexOf('#')    if (hashmarkIndex !== -1) {      url = url.slice(0, hashmarkIndex)    }
    url += (url.indexOf('?') === -1 ? '?' : '&') + serializedParams  }
  return url}
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