SampleComponent.tsx

import React from 'react';

export interface SampleComponentProps {
  firstword: string,
  secondword: string
}

export interface SampleComponentState {
  phrase: string
}

class SampleComponent extends React.Component<SampleComponentProps, SampleComponentState> {
  readonly state: SampleComponentState = {
    phrase: ''
  }

  constructor(props: SampleComponentProps) {
    super(props)
    this.state = {
      phrase: `${props.firstword} ${props.secondword}`
    }
  }

  render () {
    const { phrase } = this.state
    return (
      <div>
        <p>{phrase}</p>
      </div>
    )
  }
}

export default SampleComponent;