@mapbox/react-map-gl/src/utils/assert.js

A React wrapper for MapboxGL-js and overlay API.

// @flow
// Replacement for the external assert method to reduce bundle size
// Note: We don't use the second "message" argument in calling code,
// so no need to support it here
export default function assert(condition : any, message? : string) {
  if (!condition) {
    throw new Error(message || 'react-map-gl: assertion failed.');
  }
}