Where to apply my moment () function in a react component?

Question

I am trying to create a watch component, just to indicate the date and time in local format on a web page. I imported MomentJS using the npm command line, I moment - save webpack in my environment. Then I wrote this in my Clock.jsx component (mainly based on the React example on the website).

import React from 'react';
import Moment from 'moment';

export default class Clock extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      dateTimestamp : Date.now()
    };
  }
  tick = () => {
    this.setState({dateTimestamp: this.state.dateTimestamp + 1});
    console.log('tick');
  }
  componentDidMount() {
    this.interval = setInterval(this.tick, 1000);
  }
  componentWillUnmount() {
    clearInterval(this.interval);
  }
  render() {
    const date = this.state.dateTimestamp;
    return(
      <div className="clock"> Heure locale : {date}</div>
    );
}

}

The execution of this timestamp will increase correctly. However, when transmitting a new state element in the object, the first value (based on Date.now ()) is calculated in the constructor, but for each tick only its time stamp increases the increment of the formatted date, its first value gets stuck. Here is the code.

import React from 'react';
import Moment from 'moment';

export default class Clock extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      dateTimestamp : Date.now(),
      dateFormatted : Moment(Date.now()).toString()
    };
  }
  tick = () => {
    this.setState({dateTimestamp: this.state.dateTimestamp + 1});
    console.log(this.state.dateTimestamp);
    this.setState({dateFormatted: Moment(this.state.dateTimestamp).toString()});
    console.log(this.state.dateFormatted);
  }
  ...
  render() {
    const date = this.state.dateFormatted;
    return(
      <div className="clock"> Heure locale : {date}</div>
    );
}

}

Can anyone explain help me solve this problem, but first of all tell me what is wrong with my piece of code?

thanks

UPDATE: , , , . , .

import React from 'react';
import Moment from 'moment';

export default class Clock extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      dateFormatted : Moment().locale('fr').format('dddd Do MMMM YYYY HH:mm:ss').toString()
    };
  }
  tick = () => {
    this.setState({
      dateFormatted : Moment().locale('fr').format('dddd Do MMMM YYYY HH:mm:ss').toString()
    });
  }
  componentDidMount() {
    this.interval = setInterval(this.tick, 1000);
  }
  componentWillUnmount() {
    clearInterval(this.interval);
  }
  render() {
    const date = this.state.dateFormatted;
    return(
      <div className="clock"> Date (locale) : {date}</div>
    );
  }
}

"" -, ( - setState()). , .

Answer 1

@KrzysztofSztompka , , . (.. , ) . , / . , , " ", . .

import React from 'react';
import Moment from 'moment';

export default class Clock extends React.Component {

  constructor(props) {
    super(props);
    this.state = {
      dateTimestamp : Date.now()
    };
    this.tick = this.tick.bind(this);
  }

  tick() {
    this.setState({
      dateTimestamp: this.state.dateTimestamp + 1
    });
  }

  componentDidMount() {
    this.interval = setInterval(this.tick, 1000);
  }

  componentWillUnmount() {
    clearInterval(this.interval);
  }

  render() {
    // Calculate the formatted date on the fly
    const date = Moment(this.state.dateTimestamp).toString();
    return(
      <div className="clock"> Heure locale : {date}</div>
    );
  }

}

Answer 2

:

tick = () => {
  var timestamp = this.state.dateTimestamp + 1;
  this.setState({
    dateTimestamp: timestamp,
    dateFormatted: Moment(timestamp).toString()
  });
}

, docs:

setState() this.state, . this.state .

setState . .