CODEWITHSUNDEEP
angularjscomponents
Krzysztof
Krzysztof

Reputation: 517

AngularJS - Run function of child controller from parent controller

I have read many questions on this but still can't find solution that will be clean and reusable enough.

What I tried and don't want to use:

Simple example

I've build simplified scenario of to present the problem.

On page there is TimerComponent that shows minutes and seconds. It have controller TimerController to change its state: start() and stop(). In example there are two of them, both presenting different values.

Timer template does not contain buttons to manipulate it - that is intentional. I want to start and stop the timer from other controller.

Child-To-Parent communication. I can pass value and function callback onTick() that will be run every second.

Parent-To-Child communication: How could I run start() or stop() functions from parent component?

timer.component.js

(function() {
    'use strict';

    TimerController.$inject = ['$interval']
    function TimerController($interval) {
        var ctrl = this;

        var interval = undefined;

        ctrl.start = start;
        ctrl.stop = stop;
        ctrl.minutes = minutes;
        ctrl.seconds = seconds;           

        function minutes() {
            return Math.floor(ctrl.value / 60);
        }

        function seconds() {
            return (ctrl.value % 60);
        }

        function start() {
            interval = $interval(function() {
                ctrl.value--;
                ctrl.onTick({ 'value': ctrl.value });
            }, 1000);
        }

        function stop() {
            $interval.cancel(interval);
        }
    }

    angular.module('app').component('timer', {
        bindings: {
            value: '<',
            onTick: '&'
        },

        templateUrl: 'timer.html',
        controller: TimerController
    });
})();

timer.html

<span ng-bind="$ctrl.minutes() + ':' + $ctrl.seconds()"></span>

app.html

<body ng-app="app" ng-controller="MainController as vm">
    <p>First timer: </p>
    <timer value="360" on-tick="vm.firstTimerTick(value)"></timer>

    <p>Second timer: </p>
    <timer value="120" on-tick="vm.secondTimerTick(value)"></timer>

    <p>
        <span ng-click="vm.startFirstTimer()">Start first timer</span>
    </p>
</body>

main.controller.js

(function() {
    'use strict';

    angular.module('app').controller('MainController', MainController);

    function MainController() {
        var ctrl = this;
        ctrl.firstTimerTick = firstTimerTick;
        ctrl.secondTimerTick = secondTimerTick;
        ctrl.startFirstTimer = startFirstTimer;

        function firstTimerTick(value) {
            console.log('FirstTimer: ' + value);
        }

        function secondTimerTick(value) {
            console.log('SecondTimer: ' + value);
        }

        function startFirstTimer() {
            /* How to run start() function of TimerController here? */
        }

        function stopFirstTimer() {
            /* How to run start() function of TimerController here? */
        }
    }
})();

Upvotes: 0

Views: 307

Answers (1)

georgeawg
georgeawg

Reputation: 48968

One approach is to use the new ngRef directive:

<timer ng-ref="vm.timerOne" value="360" on-tick="vm.firstTimerTick(value)">
</timer>

Then use it in the controller:

function startFirstTimer() {
    /* How to run start() function of TimerController here? */
    ctrl.timerOne.start();
}

The ngRef directive was introduced as a new feature with AngularJS V1.7.1.

For more information, see AngularJS ng-ref Directive API Reference.

Upvotes: 3

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