Calls to Intercom('update') should be placed in effect not in render method

[Poky85]

When ReactIntercom props changes, Intercom('update') method gets called with new values.

In ReactIntercom v1 update method is called in componentWillReceiveProps lifecycle method.
https://github.com/nhagen/react-intercom/blob/master/src/index.js#L59

In ReactIntercom v2 update method is called directly in render.
https://github.com/nhagen/react-intercom/blob/2.0/src/react-intercom.ts#L69

Side effects in React should be called after component is rendered. Otherwise render performance is affected.

Based on my profiling calling an update takes tens of miliseconds.

In version 1 Intercom('update') should be called in componentDidMount().

In version 2 Intercom('update') should be called in useEffect()

[tomdohnal]

I believe this is causing this: Intercom not initialized yet warning.
Would you be interested in a PR with a fix @nhagen ?

[ChristianJacobsen]

This repo is fairly dead, @tomdohnal.

If you look at the convo in #73 you can follow our discussion.