v d trn, chng ta truyn vo mt mng cc class. All rights reserved. Tm ra s cn bng c v hiu nng v tri nghim ngi dng l cha kha cho vic pht trin. Bnh thng vi nhng Angular App t chc nng, t module v route th chng ta c th import tt cc Module vo AppModule v thm route vo ngay AppRoutingModule. Vy vi cch implement ny, c g khc vi cch import tt c vo AppModule? Mnh va gii thiu vi cc bn cc kin thc c bn nht v Module trong Angular app mong rng bn c thm nhng kin thc hay v module v s p dng thnh cng trong d n ca mnh, https://medium.com/@cyrilletuzi/architecture-in-angular-projects-242606567e40, https://medium.com/@cyrilletuzi/understanding-angular-modules-ngmodule-and-their-scopes-81e4ed6f7407, https://hpphat.wordpress.com/2018/11/07/tim-hieu-ve-angular-module-va-tam-vuc-anh-huong-scope/?fbclid=IwAR12JQmGVxN3lBChWMr0BYhDq8znQRJf0ZwQeJpuazSsZplbwRv8WvMdwYM, https://viblo.asia/p/angular-cai-thien-hieu-nang-va-trai-nghiem-nguoi-dung-voi-lazy-loading-djeZ1BkRlWz. Vy c cc no khi chia cc FeatureModule ri th chng ta cng chia route i km cc FeatureModule khng? to ra mt module chng ta c th to th cng bng tay, hoc s dng Angular CLI bng c php, Feature Module: Gom cc component hoc service c lin quan n nhau hoc cng nm trong mt feature no thnh mt nhm, Vic tch ra cc module c mt tm nh hng rt ln n vic pht trin mt d n angular nu phn chia n hp l v khoa hc, mt d n s pht trin d dng, d bo tr, d tip cn. This work is licensed under a Creative Commons Attribution-NonCommercial- ShareAlike 4.0 International License. Tuy nhin, preload tt c cc lazy load module khng phi lc no cng l s la chn ng n. Module c import khi no bn mun cng c (tc l nhiu ln). AppModule v n l 1 phn ca BrowserModule. Injector c th bit c cch to mt object, chng ta cn cung cp cc providers, chnh l u vo ca method resolveAndCreate. M file template app.component.html thm vo cui tag chy li ng dng s thy ni dung ca Module chc nng hin th. Bn c th ch cn khai bo ng k providers cho accountService bt k feature module no (hoc c th khai bo vo appModule) u c th s dng service bt k module no. V d, c 1 accountService, v 2 module userModule v orderModule c inject vo AppModule. Bi vit ny s gii thiu v Dependency Injection trong Angular mt trong nhng tnh nng quan trng ca Angular cho n thi im hin ti ch c Angular l framework duy nht pha client cung cp DI. 2022 DigitalOcean, LLC. Make sure that all the parameters are decorated with Inject or have valid type annotations and that CPU is decorated with Injectable. Module gc c khi chy bng on m (/src/main.ts). How To Upgrade from AngularJS to Angular with ngUpgrade, DigitalOcean Kubernetes: new control plane is faster and free, enable HA for 99.95% uptime SLA. Then finally, in any feature module we can simply import the shared module without the forRoot and well have access to the shared pipes and directives without providing the service again: Thats it! A neat little trick to make it easier to work with shared modules and lazy-loaded feature modules. Cc bn c th xem console ch c 1 ln duy nht log ra counter l 1.Nu chng ta t providers Component, mi ln component c to ra s sinh ra mt instance khc. @Inject/@Injectables thm cc metadata vo class Computer, m sau ny s c s dng bi DI system. Ngay k c khi bn vit theo TypeScript nh sau: Lc bn khng bit cch lm th no bo cho DI bit kiu ca token l g v DI s khng th inject dependencies cn thit cho bn c, bn c th gp li sau y. http://tiepphan.com/thu-nghiem-voi-angular-dependency-injection-trong-angular/, https://drive.google.com/file/d/0B-ux0B5az7XuNG9FaW5YVUJ6Nm8/view?usp=sharing. Trong cc v d trc, chng ta s dng provider vi cu trc ca mt object vi cc key provide v useClass nh sau. Trong trng hp trn, @Inject/@Injectable s nh du cho DI bit tham s u tin ca hm to ca class Computer cn mt instance ca class CPU nu c nhiu tham s hn, n s cho ng th t cc tham s ca hm to DI bit cch inject instances vo.

tag selector cho component ny l app-vidu01-component, khai bo component thuc module ModuleChucnangModule sa li m nh sau, np module ny vo AppModule th m file app.module.ts v thm ModuleChucnang vo phn declare, Nh vy Module chc nng np vo AppModule, hin th Component ca Module AppModule, We'd like to help.

If you have any suggestions for improvements, please let us know by clicking the report an issue button at the bottom of the tutorial. Khi to instance ca class CPU mt context (container) bn ngoi, v truyn vo (inject) cho class Computer, trong trng hp ca JavaScript, TypeScript l truyn qua constructor ca class Computer. Lc ny tt c cc thnh phn bn trong NgModule s s dng cng instance ca token tng ng. Khi bn mun tr v mt value da vo mt iu kin u vo, hoc bn mun mi ln gi n instance ca token s cho mt instance khc nhau th bn s dng factory function nh sau. Working on improving health and education, reducing inequality, and spurring economic growth? S ra sao nu bn s dng @Injectable trong trng hp hm to c tham s l mt kiu d liu primitive. Heres a sample implementation. Khi trong class A c s tn ti ca class B, dng class B lm mt cng vic no , ta ni rng class A ang ph thuc vo class B. V d, chng ta c class Computer v class CPU nh sau: Nh v d trn, class Computer ang ph thuc vo class CPU. N sinh ra file /src/app/module-chucnang/module-chucnang.module.ts c ni dung: Vy l to ra c module chc nng c tn ModuleChucnangModule, lu file vi cu trc th mc nh trn. y chnh l lc chng ta cn n Forward References. Chng ta thay i code nh sau: V khi chy chng trnh chng ta c th inject ph thuc nh sau: Khi p dng Abstration, chng ta hon ton c th s dng tnh a hnh d dng thay i cc ph thuc. Khi ng dng c load, tt c cc components ca cc lazy module u cha c load, m chng ch thc s c load khi m ngi dng s dng n chng. https://angular.io/docs/ts/latest/cookbook/dependency-injection.html, https://edwardthienhoang.wordpress.com/2015/03/30/tan-man-ve-dependency-injection/, https://blog.thoughtram.io/angular/2015/05/18/dependency-injection-in-angular-2.html, Download PDF:https://drive.google.com/file/d/0B-ux0B5az7XuNG9FaW5YVUJ6Nm8/view?usp=sharing.

C php to ra mt module, v d module ModuleName (class) nh sau: Trong v d mu phn To ng dng Angular u tin Hoc bn cn to mt instance ca mt class c tham s ca hm to l kiu primitive. Sau y l mt mu thit k cc mudule mu mi ngi c th tham kho. Kt qu l chng ta c th d dng test, thay i linh ng cc ph thuc. Nhng module no ch cung cp services: L do chng ta s ni khi qua vn v lazyloading. n y cc bn thy vic s dng service l PostService. Ngoi ra, DI trong Angular cn mt s kin thc v Controlling Visibility vi cc decorator @SkipSelf, @Host hay @Self cc bn c th vo trang document chnh thc tm hiu thm. c tn l @NgModule khai bo, Module l mt lp cha cc thnh phn thc hin cc chc nng no . MatXModule cng nhng cc module UI theme. Sometimes youll want to create a shared module in an Angular app that defines services, pipes and directives that feature modules and lazy-loaded modules can use. Tuy nhin module Setings s c ngi dng s dng nhng vi tun sut rt thp. N cng c th c s dng bi cc Component trong mng Declarations.

Provider: ging nh mt cng thc Injector c th bit lm th no to mt instance ca mt ph thuc. Nu mun s dng property cpu trong class Computer, chng ta phi khi to u, v nu khng khi to chng ta khng th s dng cc method ca property . Scope ca nhng component (c khai bo trong thuc tnh declarations) ch c th s dng c trong ni b module . Ngay khi bt u khi to mt d n Angular, chng ta thy ngay mt module mc nh l AppModule, hy cng xem n c g nh, NOTE: K t version ca Angular 6, cc service khng cn ng k trong module m chng ta c th s dng t kha providedIn: root xc nh tm nh hng ca service, khi s dng c php ny mc nh service c th s dng bt c u trong app, n tng ng vi vic service c import ngay AppModule, Khi to module nh th no => Cu tr li l c, v chnh l preload, Vy cch d dng ra sao? Vn pht sinh by gi, nu chng ta mun thay instance bng mt instance ca mt class CPU khc, lc ny chng ta bt buc phi vit li class Computer, ngay k c vic test chng trnh cng kh khn v chng ta kh thay i instance cho vic mock d liu test. y l mt ng dng email client nn module Email s c s dng rt rt thng xuyn. Lc ny mi instance ca Component/Directive X s s dng mt instance ca token (khng phi dng multiple) tng ng. V d: trong, bootstrap: nh ngha component gc ca module. V phn ny mnh s khng thc hin demo hay v d bn c th tham kho bi vit ny, kh hay v iu : y nha! Sign up for Infrastructure as a Newsletter. Tm hiu v module, cc loi module, khai bo v s dng module trong Angular. Trong thc t, chng ta thng khai bo cc services cp Module s dng xuyn sut trong chng trnh. Bng cch , cc Component c th ph thuc vo Interface Abstraction thay v ph thuc vo class c th, gip d dng kim th, bo tr, nng cp. Thc cht l cch vit ngn gn ca mt mng object c dng nh sau: Chng ta c object vi key provide, y l token DI system map vi token m @Inject/@Injectable m t. iu ny tht tuyt phi khng no, chng ta khng cn vit li class Computer, khng cn chy li tt c cc test case lin quan, c mng s gim i rt nhiu. Instead, we define a static forRoot method in the modules class that returns an object that implements Angulars ModuleWithProviders interface. Chng ta s bt u nhm ln khi scope ca component/directive/pipe (mnh gi tt chung l component) s khng ging vi service. Trong Angular chng ta c kh nhiu module trong 1 ng dng vy chng ta phi import cc module theo cch nh th no? Quay tr li vn khi chng ta cn thay i mt class khc m vn s dng token trn, chng ta ch cn bo DI class chng ta cn m khng phi sa token class cn ph thuc.

Khi khi to mt d n hy xem xt k, v nn to ra mt rule thng nht trong qu trnh pht trin khi mi ngi to mt module hay thm nhng component s khng lm ph v cc quy tc mi ngi ang lm. Chng ta vn c th thy c nhng service c provide AppModule. Gi s to ra mt component c tn l Vidu01Component s dng cho module ny g lnh sau: N sinh ra cc file trong th mc /src/module-chucnang/vidu01-component v trong c nh ngha y l blog c nhn, ti ghi chp v chia s nhng g ti hc c y v kin thc lp trnh PHP, Java, JavaScript, Android, C# v cc kin thc cng ngh khc nh du mt dependency l optional c cng c, khng c cng c chng ta s dng@Optionaldecorator. template ca AppModule s dng n selector app-vidu01-component. Tm li, chng ta s dng @Injectable vi cc kiu d liu t nh ngha class m chng ta to ra. Hy cng xem v d ca mnh nh: V d mt app v giao dc c 3 role l admin, teacher v student.

Factory c th c dependencies, lc chng ta s dng key deps: Khi c nhiu providers c cng gi tr ca key provide v khng s dng config multi: true th provider no thm vo sau cng s win. Nu Component/Directive Y cng dng n Dependency ging X, th instance ca dependency s dng trong X v Y l khc nhau. declarations: Dng khai bo nhng thnh phn chng ta s dng trn template (thng ch yu l cc component, directive v pipe). The one little hiccup is that services, which are normally supposed to act as singletons, could end up being provided multiple times, especially for lazy-loaded modules.

Ti sao c 2 cch m t cho cng mt vn . Angular cung cp mt cch extend PreloadingStrategy xc nh mt ty chnh chin lc Preload ch ra iu kin cho vic preload cc lazy load module. Tuy nhin, c mt iu vn cha c tt cho lm, l cc module ch c load khi m ngi dng s dng n. cp Component/Directive, bn khai bo cc provider vo mng providers trong config ca @Component/@Directive decorator. Khi c token, DI system s c key tip theo, trong trng hp trn l useClass, vi key trn n s to instance ca class tng ng. Cc bn c th on c mu thit k trn chnh l Dependency Injection (DI), chi tit hn l constructor injection. Chng ta c th s phi ti nhng modules m ngi dng c th rt t khi chuyn hng n. Trong ng dng Angular, bn c th cung cp provider 2 cp : Module v Component/Directive. Vi Angular s dng n decorator V d chng ta s dng token CPU nhng dng class OCCPU nh sau chng hn: Sau khi Injector khi to cc objects v inject cc dependencies cn thit, chng ta c th ly ra c object m chng ta mong mun vi phng thc get: n thi im ny, mi khi bn gi injector.get cho provider dng useClass s lun nhn c cng mt object singleton. DI trong Angular bao gm 3 thnh phn sau y: Injector: l mt object c cha cc API chng ta to cc instances ca cc ph thuc. Chng ta s c 2 cch khi to nh sau: i vi cch 1, chng ta hard-coded khi khi to nh sau: Gi s lc ny chng ta chy chng trnh vi on code nh sau: on code trn khng c g c bit, chng ta khi to instance ca class CPU bn trong contructor ca class Computer. i vi component, s khng c thay i, chng ta vn import module nh trn (tc l import commonModule v cc module cung cp components). Nhng Module c tn AppModule l module gc, n c dng khi chy ng dng, cn li th l loi Module chc nng. Cu tr li l c. trnh nhp nhng token, chng ta s dng OpaqueToken (Angular 2) hoc InjectionToken (ch c trong Angular 4+) to cc unique token. c bit i vi cc thit b di ng hay nhng kt ni bng thng thp. Tuy nhin vi nhng d n ln vic load tt c cc module cng lc khi ti trang s c th gy chm tr lm gim tri nghim ngi dng, hn na vic vit tt c cc route vo AppRoutingModule cng s gy kh trong qu trnh pht trin file qu di cng gy c ch trong qu trnh pht trin. DigitalOcean makes it simple to launch in the cloud and scale up as you grow whether youre running one virtual machine or ten thousand. Di y l mt on code trch ra t Angular Forms module validate mt field l required: Nh bn c th thy, Angular khai bo provider cn s dng n class khai bo ngay sau n. By gi t ra tnh hung, bn mun to mt provider m class bn nh ngha sau khi to provider th s th no. Trng hp token v class ging nhau nh trn, chng ta c th vit gn li nh cp trn. Bt k module no cung cp component, directive, pipe. Nu module c import s dng cc component, chng ta s phi import vo cc module no chng ta mun s dng v scope ca component ch c scope locally. Kt qu cui cng ca API_ENDPOINT s l http://tiepphan.com/thu-nghiem-voi-angular-dependency-injection-trong-angular/. Chng ta c th ci thin code trn bng cch s dng cch 2, vi vic inject cc ph thuc. trong phn bootstrap phi khai bo cc component khi chy. Ngoi cch trn chng ta c th s dng mt s cch di y: Nu bn s dng token nh sau, value s c truyn vo thay v to instance ca class. C nhiu token c th cng s dng mt token c. Trong trng hp bn mun mt token c th c nhiu value, lc ny bn c th s dng multiple nh sau: Khi kt qu nhn c l mt mng cc gi tr. Copyright 2017 to present - tiepphan.com All rights reserved. Let's register a Viblo Account to get more interesting posts. Chng ta s dng ReflectiveInjector ly c object ca class Computer chnh l Injector thng qua method resolveAndCreate. , c module l AppModule c khai bo file src/app/app.module.ts: ng dng Angular c 2 loi Module l module gc v module chc nng. Dependency: l mt object ca mt kiu d liu cn phi khi to. Nu module c import s dng cc service, chng ta ch nn import n 1 ln trong module chnh. Vi mi route ny mnh s chia n thnh mi feature module, trong mi feature module mnh s c mt file route nm trong module , nh ngha cc route lin quan n cc mn hnh trong role , Hy ch n : RouterModule.forChild(routes) y nh, Nh cch implement trn, ta c th hiu rng vi role admin khi ta tra cp cc trang trong module th path lc no cng bt u bng "admin" v d 'admin/users', 'admin/users/1', tng t vi student v teacher, Vi 3 FeatureModule kia chng khng cn phi thm trc tip vo AppModule, vi cch implement kia chng ta thc vic c LazyLoad Module, tc ta khi no ngi dng vo nhng ng dn ca tng feature th module mi c load, tc l Khi vo ng dn ban u v d: localhost:4200, th nhng Feature Module kia u cha c load, khi vo ng dn chng hn localhost:4200/admin/users th module admin mi c load. Luckily for us however, theres an easy fix for that specific use-case by defining a static forRoot method in the shared module that returns a ModuleWithProviders object.