call.md

🏠   →   Documentation   →   Built-In Functionality   →   call

Other Predicates:   attributes ・ callLifeCycleHook ・ call ・ clicked ・ debug ・ detectChanges ・ emit ・ provider ・ state ・ waitFakeAsync

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This predicate resolves the call-target using the given TargetResolver, then calls the specified method and runs change detection afterwards.

Signature

call(resolver: TargetResolver<Html, Component, Target>, methodName: keyof Target, args?: any[]);

where the type constraint Html and Component refers to the HTML- and component-type of the subject associated with this predicate; and the Target constraint determines the target-type that is resolved by the passed TargetResolver.

Please Note

the call predicate is one of the few predicates that is additionally baked into ngtx' base api; so the following code example are doing one and the same thing:

When(host)
  .does(call(componentMethod, 'open'))
  .expect(host)
  .to(haveState({ open: true }));

and:

When(host)
  .calls((componentMethod, 'open'))
  .expect(host)
  .to(haveState({ open: true }));

This was done in order to improve the readability for this very common use case.

Examples

import {
  state,
  call,
  injected,
  haveState,
  componentMethod,
} from '@centigrade/ngtx';

class the {
  static DropDownItem() {
    return get(DropDownItemComponent);
  }
}

it('should set the item-value as value of the drop-down when calling activate on it', () => {
  When(the.DropDownItem)
    .has(state({ value: 'Item 1' }))
    .and(call(componentMethod, 'activate')) // calls activate on the DropDownItem
    .expect(the.DropDown)
    .to(haveState({ value: 'Item 1' }));
});

import {
  state,
  call,
  injected,
  haveState,
  haveEmitted,
  nativeMethod,
} from '@centigrade/ngtx';

it('[RadioButton] should be selected after calling RadioGroup.select', () => {
  When(host)
    .has(state({ selected: false, value: 'Item 1' }))
    .and(call(injected(RadioGroupService), 'select', ['Item 1']))
    .expect(host)
    .to(haveState({ selected: true }));
});

it('[ContextMenu] should emit the close event on blur', () => {
  When(host).calls(nativeMethod, 'blur').expect(host).to(haveEmitted('close'));
});