timothym timothym - 1 year ago 108
AngularJS Question

$onInit does not immediately have bindings data

I have this component in my app:

<actions-bar actions="$ctrl.actionsBarData"></actions-bar>

Here is the controller / component definition:

.component('actionsBar', {
controller: 'actionsBarController',
bindings: {
actions: '<'

.controller('actionsBarController', function() {

var vm = this;

vm.$onInit = function() {
setTimeout(function() {
}, 500);

Take note of the two
statements within
. In the browser the first logging statement prints
. The second statement, wrapped in
correctly prints out the

According to the Angular docs:

$onInit() - Called on each controller after all the controllers on an
element have been constructed and had their bindings initialized

If the bindings have been initialized, why is the data not immediately available? Why must I set a delay of 500ms before it is available?

isn't the solution here, how can I reliably access the bindings data within my controller? It appears that this is correct lifecycle hook to use, and none of the other hooks appear to be what I want in this case.

Answer Source

This is because while the bindings have been initialized in the controller, they haven't necessarily been initialized where they are coming from. If you are populating your binding with an async call, the object is going to be undefined or empty.

$onChanges allows you to inspect changes that happen to your bindings.

vm.$onChanges = function (changesObj) {

If what I described above is happening, this will fix it for you.

EDIT: a word

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