像app.module.ts进口的，
import {NgbModule} from '@ng-bootstrap/ng-bootstrap';
添加它
imports:[NgbModule.forRoot()]
在编译时它给
WARNING in ./~/@ng-bootstrap/ng-bootstrap/datepicker/datepicker-input.js
188:12-21 "export 'Renderer2' was not found in '@angular/core'
WARNING in ./~/@ng-bootstrap/ng-bootstrap/modal/modal-window.js
61:12-21 "export 'Renderer2' was not found in '@angular/core'
WARNING in ./~/@ng-bootstrap/ng-bootstrap/popover/popover.js
119:12-21 "export 'Renderer2' was not found in '@angular/core'
WARNING in ./~/@ng-bootstrap/ng-bootstrap/buttons/radio.js
108:12-21 "export 'Renderer2' was not found in '@angular/core'
WARNING in ./~/@ng-bootstrap/ng-bootstrap/buttons/radio.js
212:12-21 "export 'Renderer2' was not found in '@angular/core'
WARNING in ./~/@ng-bootstrap/ng-bootstrap/typeahead/typeahead.js
224:12-21 "export 'Renderer2' was not found in '@angular/core'
WARNING in ./~/@ng-bootstrap/ng-bootstrap/tooltip/tooltip.js
131:12-21 "export 'Renderer2' was not found in '@angular/core'
webpack: Compiled with warnings.
什么可能是错误的初始化，谁能帮助？ 谢谢。
