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javascriptarraysmeteorhelper
Little Brain
Little Brain

Reputation: 2837

How to change a value in a Reactive Array and rerun the helper

I'm using the Reactive Array package in Meteor and cannot figure out how to change a value in the array and have the helper rerun. This is such a basic thing, I must be missing something obvious but I've not been able to find an answer. Here's my code:

On the client:

test_arr = new ReactiveArray([3]);

Helper:

UI.registerHelper('array_test', function(){
  return test_arr.list();
});

In a template:

{{array_test}}

On screen I see '3' as expected, but if I change the value of the reactive array with this:

test_arr[0] = 4

nothing changes on screen, even though if I run test_arr.list() in the console, I see [4]. If I push a new value with:

test_arr.push(5)

then the helper reruns and I see 4,5 on the screen, correctly. So the value had been changed, but the helper did not rerun until I performed an unrelated 'push' operation.

I can't see anything in the docs about updating a value, only adding and removing values.

Is there any way to update a value in a reactive array, reactively?

Upvotes: 2

Views: 987

Answers (2)

MasterAM
MasterAM

Reputation: 16478

You can use ReactiveArray.splice() to replace elements in a reactive array, or even create a convenience method that deals with a single element:

ReactiveArray.prototype.setAt = function(pos, item) {
  return this.splice(pos, 1, item);
};

arr = new ReactiveArray(['a', 'b', 'c']);
// ["a", "b", "c"]

arr[0];
// "a"

arr.setAt(0, "newVal");
// ["a"]

arr[0];
// "newVal"

Upvotes: 1

vasilyk
vasilyk

Reputation: 162

Look like this packages doesn't support reactive source when you set value in array by index. Try to check this one package.

Upvotes: 0

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