cypress/packages/server/lib/util/proxy.js

const os = require('os')
const getWindowsProxy = require('@cypress/get-windows-proxy')

module.exports = {
  _getWindowsProxy () {
    return getWindowsProxy()
  },

  _normalizeEnvironmentProxy () {
    if (!process.env.HTTPS_PROXY) {
      // request library will use HTTP_PROXY as a fallback for HTTPS urls, but
      // proxy-from-env will not, so let's just force it to fall back like this
      process.env.HTTPS_PROXY = process.env.HTTP_PROXY
    }

    if (!process.env.NO_PROXY) {
      // don't proxy localhost, to match Chrome's default behavior and user expectation
      process.env.NO_PROXY = 'localhost'
    }
  },

  loadSystemProxySettings () {
    if (process.env.HTTP_PROXY !== undefined) {
      this._normalizeEnvironmentProxy()

      return
    }

    if (os.platform() === 'win32') {
      const windowsProxy = this._getWindowsProxy()

      if (windowsProxy) {
        process.env.HTTP_PROXY = process.env.HTTPS_PROXY = windowsProxy.httpProxy
        process.env.NO_PROXY = process.env.NO_PROXY || windowsProxy.noProxy
      }

      this._normalizeEnvironmentProxy()

      return 'win32'
    }
  },
}