[Fleet] Use type-only imports where possible (#92979) (#93268)

## Summary

Use [type-only `import`](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-and-export) to differentiate between runtime values and (erasable) TS types.

<img width="1499" alt="Screen Shot 2021-02-27 at 6 34 46 PM" src="https://user-images.githubusercontent.com/57655/109403323-84e32c80-792a-11eb-94b7-854d0e5c3e99.png">

Allows Babel and `tsc` to make some optimizations since it can be sure what can be erased.

It can also be helpful in situations like below which highlights that even though `KibanaAssetType` and `KibanaSavedObjectType` are named a certain way and from `common/types`, they are JS values _not_ TS types. They are `enum`s which means they are JS objects at runtime; not eliminated at runtime.

https://github.com/elastic/kibana/blob/d92a1a08d89accc2fa303b1355a9e222f9b6d090/x-pack/plugins/fleet/common/types/models/epm.ts#L41-L63

# Conflicts:
#	x-pack/plugins/fleet/server/services/index.ts

x-pack/plugins/fleet/common/constants/agent_policy.ts

@@ -6,7 +6,8 @@
  */
 
 import { defaultPackages } from './epm';
-import { AgentPolicy } from '../types';
+import type { AgentPolicy } from '../types';
+
 export const AGENT_POLICY_SAVED_OBJECT_TYPE = 'ingest-agent-policies';
 export const AGENT_POLICY_INDEX = '.fleet-policies';
 export const agentPolicyStatuses = {

x-pack/plugins/fleet/common/constants/output.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { NewOutput } from '../types';
+import type { NewOutput } from '../types';
 
 export const OUTPUT_SAVED_OBJECT_TYPE = 'ingest-outputs';
 

x-pack/plugins/fleet/common/mocks.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { NewPackagePolicy, PackagePolicy } from './types';
+import type { NewPackagePolicy, PackagePolicy } from './types';
 
 export const createNewPackagePolicyMock = (): NewPackagePolicy => {
   return {

x-pack/plugins/fleet/common/services/agent_status.ts

@@ -6,7 +6,7 @@
  */
 
 import { AGENT_POLLING_THRESHOLD_MS, AGENT_SAVED_OBJECT_TYPE } from '../constants';
-import { Agent, AgentStatus } from '../types';
+import type { Agent, AgentStatus } from '../types';
 
 export function getAgentStatus(agent: Agent, now: number = Date.now()): AgentStatus {
   const { last_checkin: lastCheckIn } = agent;

x-pack/plugins/fleet/common/services/full_agent_policy_kibana_config.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { FullAgentPolicyKibanaConfig } from '../types';
+import type { FullAgentPolicyKibanaConfig } from '../types';
 
 export function getFullAgentPolicyKibanaConfig(kibanaUrls: string[]): FullAgentPolicyKibanaConfig {
   // paths and protocol are validated to be the same for all urls, so use the first to get them

x-pack/plugins/fleet/common/services/full_agent_policy_to_yaml.ts

@@ -6,7 +6,7 @@
  */
 
 import { safeDump } from 'js-yaml';
-import { FullAgentPolicy } from '../types';
+import type { FullAgentPolicy } from '../types';
 
 const POLICY_KEYS_ORDER = [
   'id',

x-pack/plugins/fleet/common/services/is_agent_upgradeable.test.ts

@@ -6,7 +6,7 @@
  */
 
 import { isAgentUpgradeable } from './is_agent_upgradeable';
-import { Agent } from '../types/models/agent';
+import type { Agent } from '../types/models/agent';
 
 const getAgent = ({
   version,

x-pack/plugins/fleet/common/services/is_agent_upgradeable.ts

@@ -7,7 +7,7 @@
 
 import semverCoerce from 'semver/functions/coerce';
 import semverLt from 'semver/functions/lt';
-import { Agent } from '../types';
+import type { Agent } from '../types';
 
 export function isAgentUpgradeable(agent: Agent, kibanaVersion: string) {
   let agentVersion: string;

x-pack/plugins/fleet/common/services/license.ts

@@ -6,7 +6,7 @@
  */
 
 import { Observable, Subscription } from 'rxjs';
-import { ILicense } from '../../../licensing/common/types';
+import type { ILicense } from '../../../licensing/common/types';
 
 // Generic license service class that works with the license observable
 // Both server and client plugins instancates a singleton version of this class

x-pack/plugins/fleet/common/services/limited_package.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { PackageInfo, AgentPolicy, PackagePolicy } from '../types';
+import type { PackageInfo, AgentPolicy, PackagePolicy } from '../types';
 
 // Assume packages only ever include 1 config template for now
 export const isPackageLimited = (packageInfo: PackageInfo): boolean => {

x-pack/plugins/fleet/common/services/package_policies_to_agent_inputs.test.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { PackagePolicy, PackagePolicyInput } from '../types';
+import type { PackagePolicy, PackagePolicyInput } from '../types';
 import { storedPackagePoliciesToAgentInputs } from './package_policies_to_agent_inputs';
 
 describe('Fleet - storedPackagePoliciesToAgentInputs', () => {

x-pack/plugins/fleet/common/services/package_policies_to_agent_inputs.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { PackagePolicy, FullAgentPolicyInput, FullAgentPolicyInputStream } from '../types';
+import type { PackagePolicy, FullAgentPolicyInput, FullAgentPolicyInputStream } from '../types';
 import { DEFAULT_OUTPUT } from '../constants';
 
 export const storedPackagePoliciesToAgentInputs = (

x-pack/plugins/fleet/common/services/package_to_package_policy.test.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { PackageInfo } from '../types';
+import type { PackageInfo } from '../types';
 import { packageToPackagePolicy, packageToPackagePolicyInputs } from './package_to_package_policy';
 
 describe('Fleet - packageToPackagePolicy', () => {

x-pack/plugins/fleet/common/services/package_to_package_policy.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import {
+import type {
   PackageInfo,
   RegistryPolicyTemplate,
   RegistryVarsEntry,

x-pack/plugins/fleet/common/types/models/agent.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { FullAgentPolicy } from './agent_policy';
+import type { FullAgentPolicy } from './agent_policy';
 import { AGENT_TYPE_EPHEMERAL, AGENT_TYPE_PERMANENT, AGENT_TYPE_TEMPORARY } from '../../constants';
 
 export type AgentType =

x-pack/plugins/fleet/common/types/models/agent_policy.ts

@@ -6,9 +6,9 @@
  */
 
 import { agentPolicyStatuses } from '../../constants';
-import { DataType, ValueOf } from '../../types';
-import { PackagePolicy, PackagePolicyPackage } from './package_policy';
-import { Output } from './output';
+import type { DataType, ValueOf } from '../../types';
+import type { PackagePolicy, PackagePolicyPackage } from './package_policy';
+import type { Output } from './output';
 
 export type AgentPolicyStatus = typeof agentPolicyStatuses;
 

x-pack/plugins/fleet/common/types/models/epm.ts

@@ -7,7 +7,7 @@
 
 // Follow pattern from https://github.com/elastic/kibana/pull/52447
 // TODO: Update when https://github.com/elastic/kibana/issues/53021 is closed
-import { SavedObject, SavedObjectAttributes, SavedObjectReference } from 'src/core/public';
+import type { SavedObject, SavedObjectAttributes, SavedObjectReference } from 'src/core/public';
 import {
   ASSETS_SAVED_OBJECT_TYPE,
   agentAssetTypes,
@@ -16,8 +16,8 @@ import {
   installationStatuses,
   requiredPackages,
 } from '../../constants';
-import { ValueOf } from '../../types';
-import { PackageSpecManifest, PackageSpecScreenshot } from './package_spec';
+import type { ValueOf } from '../../types';
+import type { PackageSpecManifest, PackageSpecScreenshot } from './package_spec';
 
 export type InstallationStatus = typeof installationStatuses;
 

x-pack/plugins/fleet/common/types/models/package_spec.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { RegistryPolicyTemplate } from './epm';
+import type { RegistryPolicyTemplate } from './epm';
 
 // Based on https://github.com/elastic/package-spec/blob/master/versions/1/manifest.spec.yml#L8
 export interface PackageSpecManifest {

x-pack/plugins/fleet/common/types/models/settings.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { SavedObjectAttributes } from 'src/core/public';
+import type { SavedObjectAttributes } from 'src/core/public';
 
 export interface BaseSettings {
   agent_auto_upgrade: boolean;

x-pack/plugins/fleet/common/types/rest_spec/agent.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import {
+import type {
   Agent,
   AgentAction,
   NewAgentAction,

x-pack/plugins/fleet/common/types/rest_spec/agent_policy.ts

@@ -5,8 +5,8 @@
  * 2.0.
  */
 
-import { AgentPolicy, NewAgentPolicy, FullAgentPolicy } from '../models';
-import { ListWithKuery } from './common';
+import type { AgentPolicy, NewAgentPolicy, FullAgentPolicy } from '../models';
+import type { ListWithKuery } from './common';
 
 export interface GetAgentPoliciesRequest {
   query: ListWithKuery & {

x-pack/plugins/fleet/common/types/rest_spec/common.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { HttpFetchQuery } from 'src/core/public';
+import type { HttpFetchQuery } from 'src/core/public';
 
 export interface ListWithKuery extends HttpFetchQuery {
   page?: number;

x-pack/plugins/fleet/common/types/rest_spec/data_stream.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { DataStream } from '../models';
+import type { DataStream } from '../models';
 
 export interface GetDataStreamsResponse {
   data_streams: DataStream[];

x-pack/plugins/fleet/common/types/rest_spec/enrollment_api_key.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { EnrollmentAPIKey } from '../models';
+import type { EnrollmentAPIKey } from '../models';
 
 export interface GetEnrollmentAPIKeysRequest {
   query: {

x-pack/plugins/fleet/common/types/rest_spec/epm.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import {
+import type {
   AssetReference,
   CategorySummaryList,
   Installable,

x-pack/plugins/fleet/common/types/rest_spec/output.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { Output } from '../models';
+import type { Output } from '../models';
 
 export interface GetOneOutputResponse {
   item: Output;

x-pack/plugins/fleet/common/types/rest_spec/package_policy.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { PackagePolicy, NewPackagePolicy, UpdatePackagePolicy } from '../models';
+import type { PackagePolicy, NewPackagePolicy, UpdatePackagePolicy } from '../models';
 
 export interface GetPackagePoliciesRequest {
   query: {

x-pack/plugins/fleet/common/types/rest_spec/settings.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { Settings } from '../models';
+import type { Settings } from '../models';
 
 export interface GetSettingsResponse {
   item: Settings;

x-pack/plugins/fleet/public/applications/fleet/hooks/use_config.ts

@@ -6,7 +6,7 @@
  */
 
 import React, { useContext } from 'react';
-import { FleetConfigType } from '../../../plugin';
+import type { FleetConfigType } from '../../../plugin';
 
 export const ConfigContext = React.createContext<FleetConfigType | null>(null);
 

x-pack/plugins/fleet/public/applications/fleet/hooks/use_core.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { FleetStartServices } from '../../../plugin';
+import type { FleetStartServices } from '../../../plugin';
 import { useKibana } from '../../../../../../../src/plugins/kibana_react/public';
 
 export function useStartServices(): FleetStartServices {

x-pack/plugins/fleet/public/applications/fleet/hooks/use_link.ts

@@ -5,13 +5,8 @@
  * 2.0.
  */
 
-import {
-  BASE_PATH,
-  StaticPage,
-  DynamicPage,
-  DynamicPagePathValues,
-  pagePathGetters,
-} from '../constants';
+import { BASE_PATH, pagePathGetters } from '../constants';
+import type { StaticPage, DynamicPage, DynamicPagePathValues } from '../constants';
 import { useStartServices } from './';
 
 const getPath = (page: StaticPage | DynamicPage, values: DynamicPagePathValues = {}): string => {

x-pack/plugins/fleet/public/applications/fleet/hooks/use_package_icon_type.ts

@@ -7,7 +7,7 @@
 
 import { useEffect, useState } from 'react';
 import { ICON_TYPES } from '@elastic/eui';
-import { PackageInfo, PackageListItem } from '../types';
+import type { PackageInfo, PackageListItem } from '../types';
 import { useLinks } from '../sections/epm/hooks';
 import { sendGetPackageInfoByKey } from './index';
 

x-pack/plugins/fleet/public/applications/fleet/hooks/use_request/agent_policy.ts

@@ -5,14 +5,10 @@
  * 2.0.
  */
 
-import {
-  useRequest,
-  sendRequest,
-  useConditionalRequest,
-  SendConditionalRequestConfig,
-} from './use_request';
+import { useRequest, sendRequest, useConditionalRequest } from './use_request';
+import type { SendConditionalRequestConfig } from './use_request';
 import { agentPolicyRouteService } from '../../services';
-import {
+import type {
   GetAgentPoliciesRequest,
   GetAgentPoliciesResponse,
   GetOneAgentPolicyResponse,

x-pack/plugins/fleet/public/applications/fleet/hooks/use_request/agents.ts

@@ -5,9 +5,10 @@
  * 2.0.
  */
 
-import { useRequest, UseRequestConfig, sendRequest } from './use_request';
+import { useRequest, sendRequest } from './use_request';
+import type { UseRequestConfig } from './use_request';
 import { agentRouteService } from '../../services';
-import {
+import type {
   GetOneAgentResponse,
   GetOneAgentEventsResponse,
   GetOneAgentEventsRequest,

x-pack/plugins/fleet/public/applications/fleet/hooks/use_request/app.ts

@@ -7,7 +7,7 @@
 
 import { sendRequest } from './use_request';
 import { appRoutesService } from '../../services';
-import { CheckPermissionsResponse } from '../../types';
+import type { CheckPermissionsResponse } from '../../types';
 
 export const sendGetPermissionsCheck = () => {
   return sendRequest<CheckPermissionsResponse>({

x-pack/plugins/fleet/public/applications/fleet/hooks/use_request/data_stream.ts

@@ -7,7 +7,7 @@
 
 import { useRequest } from './use_request';
 import { dataStreamRouteService } from '../../services';
-import { GetDataStreamsResponse } from '../../types';
+import type { GetDataStreamsResponse } from '../../types';
 
 export const useGetDataStreams = () => {
   return useRequest<GetDataStreamsResponse>({

x-pack/plugins/fleet/public/applications/fleet/hooks/use_request/enrollment_api_keys.ts

@@ -5,15 +5,10 @@
  * 2.0.
  */
 
-import {
-  useRequest,
-  UseRequestConfig,
-  sendRequest,
-  useConditionalRequest,
-  SendConditionalRequestConfig,
-} from './use_request';
+import { useRequest, sendRequest, useConditionalRequest } from './use_request';
+import type { UseRequestConfig, SendConditionalRequestConfig } from './use_request';
 import { enrollmentAPIKeyRouteService } from '../../services';
-import {
+import type {
   GetOneEnrollmentAPIKeyResponse,
   GetEnrollmentAPIKeysResponse,
   GetEnrollmentAPIKeysRequest,

x-pack/plugins/fleet/public/applications/fleet/hooks/use_request/epm.ts

@@ -7,7 +7,7 @@
 
 import { useRequest, sendRequest } from './use_request';
 import { epmRouteService } from '../../services';
-import {
+import type {
   GetCategoriesRequest,
   GetCategoriesResponse,
   GetPackagesRequest,
@@ -17,7 +17,7 @@ import {
   InstallPackageResponse,
   DeletePackageResponse,
 } from '../../types';
-import { GetStatsResponse } from '../../../../../common';
+import type { GetStatsResponse } from '../../../../../common';
 
 export const useGetCategories = (query: GetCategoriesRequest['query'] = {}) => {
   return useRequest<GetCategoriesResponse>({