idea: new reaction with delayed dependency check

[mayorovp]

see issue #1805

The problem of unnecessary evaluations is early shouldCompute call. While reaction can be delayed via scheduler or onInvalidate - shouldCompute is always called immediatelly. But what if we delay this call?

New reaction class can be used in React observers this way:

this[mobxReaction] = new ReactionEx(`${initialName}#${rootNodeID}.render()`, () => this.setState({}));

// ...

shouldComponentUpdate: function(nextProps, nextState) {
    return !shallowEqual(this.state, nextState) 
        || !shallowEqual(this.props, nextProps)
        || this[mobxReaction].shouldCompute()
}

[urugator]

Like it.

Could shouldComponentUpdate be delayed so much that it would somehow mess with mobx synchronous nature?

Can we somehow skip prop/state check, when the component is invalidated via Mobx (specific state field perhaps)?

[mayorovp]

Could shouldComponentUpdate be delayed so much that it would somehow mess with mobx synchronous nature?

Computeds already can delay the shouldCompute call forever.

Can we somehow skip prop/state check, when the component is invalidated via Mobx (specific state field perhaps)?

We can move this[mobxReaction].shouldCompute() call before this checks.

[mweststrate]

@mayorovp tip: if you fix the single test failing api.js, it will make this PR look more solid :). (PR's that have failing builds tend to be ignored, as they are assumed WIP)

[mayorovp]

@mweststrate but this PR is WIP

[ItamarShDev]

@mayorovp is it still WIP?

[mweststrate]

Closing (can be further discussed in #1805).