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The syntax card

Binding	Syntax	Direction
Interpolation	{{ value }}	class → view (text only)
Property	[prop]="value"	class → view
Event	(click)="fn()"	view → class
Two-way	[(ngModel)]="value"	both — it's [x] + (xChange)

Lifecycle, in order	Use for
constructor	Injection only — inputs are NOT set yet
ngOnChanges	Runs BEFORE ngOnInit, and again on every input change
ngOnInit	Load data, subscribe — runs ONCE
ngAfterViewInit	@ViewChild, DOM, chart libraries
ngOnDestroy	Unsubscribe, clear timers

Pipe	Example
date	{{ d | date:'dd/MM/yyyy' }}
currency	{{ n | currency:'INR' }}
uppercase / lowercase	{{ s | uppercase }}
json	{{ obj | json }} — debugging
async	{{ data$ | async }} — subscribes AND unsubscribes

RxJS operator	Does
map / filter / tap	Transform · drop · side effect
switchMap	Chain, cancelling the previous — search, route params
mergeMap / concatMap / exhaustMap	All at once · in order · ignore while busy
debounceTime + distinctUntilChanged	Typeahead
forkJoin	Promise.all for observables
takeUntil	Unsubscribe on destroy
shareReplay(1)	Share one execution — stops duplicate HTTP calls

The 12 things to be sure of

If you remember nothing else, remember these.

1	Angular is a framework, React is a library — DI, routing, HTTP and RxJS come in the box.
2	Constructor = injection only. Inputs aren't set yet — initialise in ngOnInit.
3	ngOnChanges fires before ngOnInit, and again on every input change. ngOnInit runs once.
4	*ngIf removes the element from the DOM — it isn't hidden, it's destroyed.
5	trackBy is React's key. Without it a reassigned array rebuilds every row.
6	providedIn: 'root' = one instance app-wide. Listing it in a component's providers quietly breaks that.
7	Reactive forms for anything real. Template-driven only for a login box.
8	Route params: subscribe to paramMap, don't read the snapshot — the component is reused.
9	An interceptor is the one place for the auth token and global error handling. Requests are immutable — req.clone().
10	Observables are lazy and cancellable. Nothing happens until you subscribe, and two subscribes = two HTTP calls.
11	switchMap cancels the previous — right for search. mergeMap doesn't — wrong for search.
12	OnPush needs immutable data. Push to an array and nothing renders; replace the array and it does.

Words that signal seniority

change detection · OnPush · immutable data · cold observable · lazy loading · tree-shakeable · provider scope · memory leak · debounce · cancel the previous request · feature module · measure first · trade-off