Leaflet Error: Invalid LatLng object: (, NaN)

Here is the solution:

I simply updated leaflet from 0.7.7 to the most recent (1.0.3) in my package.json and I ran npm install.

Btw, this is happened because you probably used the documentation of v1.x.x. It is used as below for 0.7.7;

L.circle([50.5, 30.5], 200).addTo(map);

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