Why is my react component not updating with state updates?

Question

I have a map app I built that requires some map icons to appear/disappear after a button press, but I can\'t figure out how to set it to re-render the component when I pass in a

Answer 1

React ES6 classes do not autobind this by default to non-react base member methods. Therefore, the context for this in your function makeMapEvents is not bound correctly. There are 2 ways to fix this:

Via ES7 property initializer:

makeMapEvents = (insertProps) => {
  fetch("./json/meetup.json").then((response) => {
    return response.json()
  }).then((response) => {
    /* eventually returns new events object based on insertProps */
    this.setState({events: response});
  })
};

Via binding in constructor:

constructor(props) {
  (props);
  this.state = {
    events: [{venue: {lat: 2, lon: 1}}],
    sports: ["baseball", "football",  "paddle", "soccer", "boxing", "dart", "biking", "golf", "hockey", "inline-skating", "tennis", "volleyball", "skateboard", "kickball", "bowling", "pool", "ride", "hike", "ice-skating"]
  };

  this.makeMapEvents = this.makeMapEvents.bind(this) // << important line


}