Reactjs pass variable to function from another class

Question

Request.js

export default class Request extends React.Component {
getForm(e) {
  let v = validator(document.getElementById('myinput')); // here is should call function from another class
}
render(){
  return(
      <form onSubmit={this.getForm.bind(this)}>
        <RequestValidator/> // here is I called second class
        <Input id="myinput" value="65"/>
      </form>
    }
  }
}

RequestValidator.js

export default class RequestValidator extends React.Component {
  validator = (e) => { // here is the target function
    console.log(e.value);
  }
}

What I want to do is, pass a variable (#myinput value) from Request compontent class to a function (validator) in another compontent class (RequestValidator).

What I have done so far is above codes, but I got error:

'validator' is not defined no-undef

Please indent your code, it looks very messy.

Ante Gulin
– Ante Gulin

2019-08-21 19:09:53 +00:00
Commented Aug 21, 2019 at 19:09 — Ante Gulin
– Ante Gulin, Commented Aug 21, 2019 at 19:09

Federkun · Accepted Answer · 2019-08-21 19:29:42Z

2

You can do that using ref. You create one in your parent component:

class Request extends React.Component {
    constructor(props) {
        super(props)
        this.requestValidatorRef = React.createRef();
    }

then you pass it to the child component:

<RequestValidator ref={this.requestValidatorRef} />

at this point you should be able to call your method like this:

getForm(e) {
  this.requestValidatorRef.current.validator(e) // ...
}

edited Aug 21, 2019 at 19:29

answered Aug 21, 2019 at 19:10

Federkun

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6 Comments

Jack The Baker Over a year ago

And it return: TypeError: Cannot read property 'current' of undefined

Federkun Over a year ago

you may need to share your attempt. current can be undefined, because it is set later

farbod Over a year ago

Everything is right. but need one change to work. Just remove .current from this.requestValidatorRef.current.validator(e)

Jack The Baker Over a year ago

No, it is my mistake, it call function, but my code inside the function return nothing, so this problem solved, thanks

farbod Over a year ago

By the way document.getElementById('myinput') is not react syntax. react using ref for this.

|

unfixedbug · Accepted Answer · 2019-08-21 20:09:51Z

0

If you want to pass parameter to another class in reactjs you should use props. Also variable in requestvalidator class have to use prop name. But in your case RequestValidator and Input components are different. In main component class call like this:

  <UserInput
         titles={this.state.titles}
    />

In UserInput component use this prop like this:

class UserInput extends React.Component {
      componentDidMount() {
        console.log(" titles from main class:", this.props.titles);
      }
}

answered Aug 21, 2019 at 20:09

unfixedbug

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