computed property is not updated when its dependencies are binded with inline data

[iraklisg]

Vue.js version

2.0.1

Reproduction Link

https://jsfiddle.net/3xgv2e3n/2/

Steps to reproduce

Replace my_tasks in <task-list :tasks="my_tasks"></task-list> with an inline list e.g. [{body: 'Hello all', completed: false},{body: 'Goodbye all', completed: false}]

What is Expected?

It is expected the remaining computed property to be updated when user clicks on a task (i.e toggle its complete state from false to true and vice-versa), as it happens in case of binding the my_tasks data with tasks prop

What is actually happening?

The computed property is not re-evaluated when its dependency (i.e. task.completed ) changes.
Note that the JSfiddle code works fine with Vue 1.0.26, when replacing the my_tasks with an inline list [{/*...*/},{/*...*/}, /*...*/]

[LinusBorg]

Can't check the repro right now, but this could be because migrating props is an anti pattern in 2.0: http://vuejs.org/guide/migration.html#Prop-Mutation-deprecated

[yyx990803]

Inline props are same as an immutable value, because every time the parent re-renders, the mutated child prop will be reset back to the inline value. Relying on reactively mutating an inline prop is a usage that no longer makes sense, therefore these inline values are not made reactive.

If you want to allow inline props as the initial value, declare a field in your data that uses the props value:

data () {
  return {
    mutableCopy: this.immutableProp
  }
}

[zuomingcai]

when we declare a component in the template,we may want to set a initial value for its attributes but not to bind it to a parent variable.can vuejs support :prop.once ? it is much more convenient to set a initial value in template than in js code.

[LinusBorg]

This is a closed issue.

Also, your issue is a usage/support question, and the issue tracker is reserved exclusively for bug reports and feature requests (as outlined in our Contributing Guide).

We encourage you to ask it on the forum , Stack Overflow or on gitter and are happy to help you out there.