I have an application using vue.js. I generate a list of results using v-for in an array of objects. when I update the object inside nth item in array, using underscore _.extend, the view of project does not update. There is a solution for this problem at .html which indicates to use _.extend like this:

this.results.displayed[key] = _.extend({}, this.results.displayed[key], detail.items);

but the problem is when I use extend like it said, it does not update the view.

I have an application using vue.js. I generate a list of results using v-for in an array of objects. when I update the object inside nth item in array, using underscore _.extend, the view of project does not update. There is a solution for this problem at http://vuejs/guide/reactivity.html which indicates to use _.extend like this:

this.results.displayed[key] = _.extend({}, this.results.displayed[key], detail.items);

but the problem is when I use extend like it said, it does not update the view.

• javascript
• arrays
• underscore.js
• javascript-objects
• vue.js

• There's not enough information to figure out what is wrong. Can you recreate this in a fiddle? – David K. Hess Commented Feb 7, 2016 at 17:50

2 Answers 2

Vue is unable to detect the change when you set a new item by array index. To get around this, you can use the $set() method that Vue adds to the array.

var newObject = _.extend({}, this.results.displayed[key], detail.items);
this.results.displayed.$set(key, newObject);

More info here.

I solved my problem of items in v-for not updating, by making sure that the tag containing the v-for was wrapped by a tag.

It had been wrapped in a v-ons-list. And I could imagine some people wrapping it in a div tag. This is a quick possibility to eliminate before trying all the other more plicated solutions out there.