Instance method anti-pattern

a.js

/**
 * Instance method anti pattern
 */
class MyComponent extends React.Component {
  computeThatThing() {
    return this.props.a + this.props.b;
  }

  render() {
    return (
      <div>{this.computeThatThing()}</div>
    )
  }
}

/**
 * Pure function alternative
 */
function computeThatThing(a, b) {
  return a + b;
}

class MyComponent extends React.Component {
  render() {
    const result = computeThatThing(this.props.a, this.props.b);
    
    return (
      <div>{result}</div>
    )
  }
}