Cannot read property 'bind' of undefined, React.js

Question

When binding this to my addTimes function I get an error stating: Cannot read property 'bind' of undefined.

I am building in ReactjJS and Webpack. I recently had another issue recent which people suggested:

this.addTimes = this.addTimes.bind(this);

See: Cannot read property 'setState' of undefined ReactJS

class Settings extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      times: []
    };

  }
  render(){
    this.addTimes = this.addTimes.bind(this);
    Array.prototype.remove = function() {
        var what, a = arguments, L = a.length, ax;
        while (L && this.length) {
            what = a[--L];
            while ((ax = this.indexOf(what)) !== -1) {
                this.splice(ax, 1);
            }
        }
        return this;
    };

    var currentTicked = [];
    var times =[]
    function addTimes(id){
      var index = times.indexOf(id);
      if (!times.includes(id)) {
        $("input:checkbox[name=time]:checked").each(function(){
          currentTicked.push($(this).val());
          times = times.concat(currentTicked)
          times = jQuery.unique(times);
          currentTicked = [];

        });
      } else if(times.includes(id)){
        times = times.remove(id);
      }
      console.log(times);
      this.setState = {
        thims: times
      }
    }

In order to be able to bind addTimes to this in the constructor, addTimes must be a method on your class, not just a function in the render method. — Tholle
– Tholle, Commented Jul 9, 2018 at 10:32

Tholle · Accepted Answer · 2018-07-09 10:34:57Z

In order to be able to bind addTimes to this in the constructor, addTimes must be a method on your class, not just a function in the render method.

class Settings extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      times: []
    };
    this.addTimes = this.addTimes.bind(this);
  }

  addTimes(id) {
    // ...
  }
}

If you want to create addTimes in the render method, you could just bind this to the function there:

function addTimes(id) {
 // ...
}.bind(this);

Or your could make it into an arrow function instead:

const addTimes = (id) => {
  // ...
}

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