[javascript] Can I update a component's props in React.js?

After starting to work with React.js, it seems like props are intended to be static (passed in from the parent component), while state changes based upon events. However, I noticed in the docs a reference to componentWillReceiveProps, which specifically includes this example:

componentWillReceiveProps: function(nextProps) {
  this.setState({
    likesIncreasing: nextProps.likeCount > this.props.likeCount
  });
}

This seems to imply that the properties CAN change on a component based upon the comparison of nextProps to this.props. What am I missing? How do props change, or am I mistaken about where this gets called?

Much has changed with hooks, e.g. componentWillReceiveProps turned into useEffect+useRef (as shown in this other SO answer), but Props are still Read-Only, so only the caller method should update it.

Props can change when a component's parent renders the component again with different properties. I think this is mostly an optimization so that no new component needs to be instantiated.

if you use recompose, use mapProps to make new props derived from incoming props

Edit for example:

import { compose, mapProps } from 'recompose';

const SomeComponent = ({ url, onComplete }) => (
  {url ? (
    <View />
  ) : null}
)

export default compose(
  mapProps(({ url, storeUrl, history, ...props }) => ({
    ...props,
    onClose: () => {
      history.goBack();
    },
    url: url || storeUrl,
  })),
)(SomeComponent);

PROPS

A React component should use props to store information that can be changed, but can only be changed by a different component.

STATE

A React component should use state to store information that the component itself can change.

A good example is already provided by Valéry.

Trick to update props if they are array :

import React, { Component } from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  Button
} from 'react-native';

class Counter extends Component {
  constructor(props) {
    super(props);
      this.state = {
        count: this.props.count
      }
    }
  increment(){
    console.log("this.props.count");
    console.log(this.props.count);
    let count = this.state.count
    count.push("new element");
    this.setState({ count: count})
  }
  render() {

    return (
      <View style={styles.container}>
        <Text>{ this.state.count.length }</Text>
        <Button
          onPress={this.increment.bind(this)}
          title={ "Increase" }
        />
      </View>
    );
  }
}

Counter.defaultProps = {
 count: []
}

export default Counter
const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
  },
});