Change this to OK_STATUS so its clear that it's a true constant variable.

Unless I'm missing something, let's make this a state variable of the search component instead of a global variable for the module. In the constructor, declare in the state object and initialize as null. I'll annotate the rest of the code where related changes are needed.

use this.state.marker in place of the marker variable throughout this function.

Since we are managing the state in the parent,i.e, LeafletOSMMap, we then need to do it there? We can't change the state in the child right, only affect the changes through prop. I am new to React so, correct me if I am wrong or is there another correct pattern to do this?
Initially I intended to do all the marker stuff in parent component of Search so that I could affect the state, but based on the comment I figured we need to follow this approach.

this article might be helpful https://medium.freecodecamp.org/where-do-i-belong-a-guide-to-saving-react-component-data-in-state-store-static-and-this-c49b335e2a00

Redux is the most preferred way to handle store. Currently we don't use Redux in the project and redux makes me dizzy, the learning curve there with react feels too much for me to handle at present, that could be just me 😬 . I am comfortable with React's local store usage, in case we move to Redux I am back to reading.

Redux would be new to me too but I don't think we need it in this case...will read up on it this weekend to confirm. But for this, each component can have its own state and consume props passed to it. See line 10 - we already have Search component specific state, add marker key to it for tracking Search result marker instance.

Basically, I'm considering this marker to be a local state of the Search component and its SearchResult child component - it should have complete control of the marker instance independent of it's parent. My thinking being because nothing other than the actions from Search(Result) determine the existence of the marker. Though this may change once we start integrating Places detail but for now I think this is the right way to go.

ok @jkwening will make changes to hold it in the search component state.

the dizzy 💫 feeling with redux is completely normal ... we don't need to go that deep just yet 🤔

initialize a new L.marker within this block:

this.setState({
  marker: <L.marker(location)...>
})

this should remain outside the this.setState() code snippet

Also we should rename this function to "handleSelectedPlace" or some derivative of "handle..." since its handling the action of clicking on search prediction.