Tswv yim ua hauj lwm nrog Angular Components
Txheej txheem cej luam:
Tom qab ib xyoo Angular 2 tso tawm, ces tom qab ib qho tsim tawm tuaj nrog Angular 4, los yog Angular v4, tab sis tsuas hu ua “angular.” tsis hnov txog tus version naj npawb unequivocally hauv lub npe. Yeej "2" siv los ua txawv Angular JS thiab New Angular 4 moj khaum. Lub sij hawv, Angular, Siv tau nyob rau ntau hom lus xws li Dart, Yam Tshwm Sim los sis ECMAScript 5 thiab lwm tus. Thaum tus taw tes thaum Angular 2 tau muab faib, Tus Angular tsim tawm ntxiv xaiv los utilize “semantic versioning” xav versions ntxiv, Ua qhov zoo sib xws ntawm ntau versions txog zoo sib xws thiab nta tshiab pom chiv.
Versioning
Cov zauv Version yog, li no, teem raws li qhia los ntawm qhov loj. ME. THAJ. Cov digit no hloov raws li ib tug accompanying criteria:
- FEEM COOB Txhab txij thaum nws muaj ib qho incongruent hloov rau lub API. Rau Angular, Qhov no yuav yog qhov teeb meem no yog tshiab versions siv tsev qiv ntawv zoo li tsam.js los yog rxjs tau embraced tias conveys hloov kev hloov rau lub API.
- ME txhab ntxiv thaum twg ntxiv cov kev pab cuam ntxiv yog muab, Txawm li cas los, Muaj tej yam uas twb muaj lawm thiab cov API yog cia ruaj khov. Rau Angular, Qhov no yuav yog ib yam li ib cov kav dej tauj tauj raws li tus component ntawm tus framework.
- THAJ Txhab thaum ib co troubleshooting yog tswj tsis hloov cov API, Raws li cov kab nyob rau hauv nraud zoo.
Yuav tsum nyeem – Introduction to AngularJS
Qhov no yog tshiab nyob rau hauv Angular 4.4 Piav qab no loj tshiab tso yog ob yam nta tshiab xwb li inconsistent nrog lub version yav tas los. Li cas peb khawb tus tshiab nta:
Router ParamMap
Pib ntawm version 4, Nws yog conceivable rau lo lus nug ib ncig Parammap nyob rau hauv lub router, uas txhais tau tias ib tug thov kom tau cov hoob thiab queryparameter relegated rau ib hoob kawm.
Tsis ntev dhau los, tiv thaiv cov parameters tau muab tseg rau hauv lub keeb kwm yooj yim-kwv yees li, Qhov no yog qhib los ntawm utilizing tus txheem JavaScript syntax (parameterbek['parameter-npe'] ).
Qhia 1: Txheem JavaScript syntax
[chaws]
Hoob Kawm MyComponent {
sib kho kom haum: Observable<hlua>;
tswj(ntiav: ActivatedRoute) {}
NongInit() {
Qhov no... qhib = qhov no route
.queryParams
.daim ntawv qhia(params => params['session_id'] || 'Tsis muaj');
}
}
[/chaws]
Presently, Cov parameters no ntxiv yog ib daim ntawv qhia ua ib daim ntawv qhia, Li ntawd, koj yuav khiav tau raws li txoj kev straightforward hu (parameterMap.taug parameterMap.tau('parameter-npe')).
Qhia 2: Txoj kev straightforward hu
[chaws]
Hoob Kawm MyComponent {
sib kho kom haum: Observable<hlua>;
tswj(ntiav: ActivatedRoute) {}
NongInit() {
Qhov no... qhib = qhov no route
.queryParamMapa
.daim ntawv qhia(paramap => taug parammap.get('session_id') || 'Tsis muaj');
}
}
[chaws]
Siv ib daim ntawv qhia ntxiv thiab tau txais lus kom zoo dua cov ntsiab lus uas tsi ruaj ntseg. Tus qub key-esteeme qauv muaj ib tug tsi pheej hmoo (Hom Params = {[qhov tseem ceeb: hlua]: ib yam dabtsi}), Qhov twg cov parameter esteeme yuav siv txhua zaus ib zaug xwb tsi. Nrog daim ntawv qhia tshiab, tsis hnov lus, Tus parameter esteeme yog ib txoj hlua los yog ntau txoj hlua, contingent raws li txoj kev utilized.
Yuav tsum nyeem – Nyiam tsab xov xwm rau AngularJS
Animations
Functions fundamental rau animations mus taw tes no tau muab ua ib qho kev sib nrauj ntawm cov @angular/hab txhawb module, suggesting tias cov chaws ntawm lub chaws nyob incorporated continuously rau hauv ntaub ntawv. Rau abstain los ua bundles nrog superfluous expansive loj, Muaj peev xwm tau muab tso rau hauv nws lub pob heev. (Qhov no tsis yog ib tug tshiab tivthaiv tsis tau, tseem, hloov cov kev kho hloov uas twb muaj lawm yog hais tias lawv muaj animations.)
Cov tsiaj yuav muab rau cov module BrowserAnimationsModule ntawm @angular/platform-program/animations.
ntxawg: Yuav nyiam utilized nrog “lwm.”
Nws yog ib tug tseem ceeb continuous tshaj plaws rau utilize “tus txheejtxheem rendering” hauv templates qhia cov ntaub ntawv relying li ib txhia neeg mob. Qhov no yog tas los ntawm kev siv *ngif. Nyob rau lub sij hawm uas ib lub caijnyoog twg tsis tau ntsib, Tus txheeb ze thiab tag nrho cov me nyuam hais tsis ntxiv rau lub DOM-tsob ntoo. Feem ntau muaj ib yam liwise yuav tsum tau txwv cov ntaub ntawv txwv, Nws tseem ceeb heev uas yuav tau npaj ib yam mob zoo sib xws tsuas sib txawv lwm *ngIf.
Qhov no muaj ib co phem implication for intelligibility thiab viability of code – tag nrho tej yam uas xav tau, Koj yuav tau noj ib txoj kab ntau ntawm txoj kab uas code thaum actualizing ob peb.
Hauv Angular 4, Cov ntaub ntawv no yuav tsum khom nrog ib tug tshiab khiv nyob nrog lwm tus. Tej zaum nws yog startling rau ob peb, Angular utilization ib independently siv template fragment, uas nyob rau hauv cov ntaub ntawv else-case yuav tsum utilized xwb ntawm qhov kev sib nrauj teev nrog *ngIf.
Cov qauv no delineates lub txim nyob rau hauv chaws laus thiab tshiab syntax. Siv rooj plaub no yog los qha tau qhov chaw nyob hauv lub npe ntawm ib tus neeg tau uas kos npe rau hauv, los yog ib tug ntes tau rau ib tus neeg tau txais kev pab tsis kos npe rau hauv.
Qhia 3: Laus thiab tshiab syntax
Qub syntax:
[chaws]
Logged li {{tus sau phau ntawv.username}}
Thov caws: <khawm>ntxaij</khawm>
[/chaws]
Tshiab syntax:
[chaws]
<ng-template #needsLogin>
Thov caws: <khawm>ntxaij</khawm>
</ng-template>
Eingeloggt als {{tus sau phau ntawv.username}}
[/chaws]
Cov kev pab cuam ntawm *ngif hauv lub teb ntawm reactive programming tau enhanced thaum uas muaj cov async-pipe. Yog thaum ntawd kis conceivable rau “muas” (thiab “Thim”) rau cov khoom uas tsis yog cov khoom zoo ib yam li observables thiab xws li hauv ib template los ntawm utilizing cov async-Pipe. Cov tshiab *NgIf-Syntax tam sim no ua rau nws conceivable mus nyiam ntxiv ib tug nyob ze template variable rau cov tom qabeffect ntawm cov yog-nqe lus. Nyob rau hauv cov qauv hauv qab lub detectable, teev cia rau hauv lub qhov ncauj, yog tswm los ntawm cov async-pipe. Lub sij hawm yuav tsum utilized hauv lub template los ntawm txoj kev rau cov neeg siv ntau yam khoom.
[chaws]
<ng-template #loading>
Loading neeg siv cov ntaub ntawv…
</ng-template>
{{username }}
[/chaws]
Nco ntsoov tias cov async-Pipe yog certifiably tsis yog ib qho tseem ceeb precondition rau utilizing tus tshiab syntax, tiam sis xwb siv rau kev siv rau lub hom phiaj ntawm no precedent. Siv lwm pipe los yog tsis Muaj Pipe xijpeem yuav nyiam ua hauj lwm.
Dynamic Components nrog NgComponentOutlet
Cov tshiab *ngComponentOutOutlet-Directive ua rau nws conceivable yuav tsim dynamic components decisively. Txog li no taw tes, Nws kuj yog ib tug nqi uas ua hauj lwm rau manufacture thiab xa qhov chaw dynamically nyob runtime. Nws yog insufficient kom txhob kov ib co HTML cias! Angular yuav tsum qhia txog tus ya thiab ntxiv rau lub lifecycle, tsis kam muab cov ntaub ntawv pov thawj thiab hloov rov qab. Cov qub kev qub rau kev siv ComponentFactory hauv no txoj kev uas muaj npaum li cas programming ua hauj lwm.
Cov qauv accompanying qhia tau hais tias zoo li cas zoo li nrog *ngComponentOutOlet:
Qhia 4: Uas qhia cov qauv uas qhia qauv
[chaws]
@Component({
selector: 'App-first-time-time qhua',
Template: ‘
<h1>Txais tos rau peb phab 4!</h1>
’,
})
export class FirstTimeVitorComponent {}
@Component({
selector: 'App-frequent-qhua',
Template: ‘
<h1>Zoo siab koj rov los lawm!</h1>
’,
})
export class Frequentismponent Frequismponent {}
@Component({
selector: 'app-root',
Template: `
<h1>Nyob zoo Angular v4!</h1>
<ng-container *ngComponentOutlet=”Zoo siab tos txais”></thawv ntim>
`,
})
export class App implements Oninit{
txais tos = FirstTimeVitorComponent;
NongInit() {
Yog hais tias(!No.user.isfirstVisite){
Qhov no.alert = Frequismponent Frequismponent;
}
}
}
[/chaws]
Yuav tsum nyeem – Ntau tsab xov xwm hauv ntej-kawg framework
Sau Bio: Alex Jone yog ib tug HR thiab Recruitment nyob Alliance Recruitment Acruitment- Ib qho IT Recruitment Agency. Nws tshwj xeeb hauv kev pab nrog recruiting thoob ntiaj teb recruiting, cov neeg ua haujlwm, HR cov kev pab thiab careers tswv yim pab rau teb chaws thiab thoob ntiaj teb lag luam.
