Form fields lose focus when input value changes

[donalmurtagh]

I'm trying to render a FormWithConditionals and a FormModelInspector. The latter is a very simple component that shows the current formData.

The source code is given below:

import React from 'react';
import PropTypes from 'prop-types';
import Engine from "json-rules-engine-simplified";
import Form from "react-jsonschema-form";
import applyRules from "react-jsonschema-form-conditionals";

function FormModelInspector (props) {

  return (
    <div>
      <div className="checkbox">
        <label>
          <input type="checkbox" onChange={props.onChange} checked={props.showModel}/>
          Show Form Model
        </label>
      </div>
      {
        props.showModel && <pre>{JSON.stringify(props.formData, null, 2)}</pre>
      }
    </div>
  )
}

class ConditionalForm extends React.Component {

  constructor (props) {
    super(props);
    this.state = {
      formData: {},
      showModel: true
    };
    this.handleFormDataChange = this.handleFormDataChange.bind(this);
    this.handleShowModelChange = this.handleShowModelChange.bind(this);
  }

  handleShowModelChange (event) {
    this.setState({showModel: event.target.checked});
  }

  handleFormDataChange ({formData}) {
    this.setState({formData});
  }

  render () {
    const schema = {
      type: "object",
      title: "User form",
      properties: {
        nameHider: {
          type: 'boolean',
          title: 'Hide name'
        },
        name: {
          type: 'string',
          title: 'Name'
        }
      }
    };

    const uiSchema = {};

    const rules = [{
      conditions: {
        nameHider: {is: true}
      },
      event: {
        type: "remove",
        params: {
          field: "name"
        }
      }
    }];

    const FormWithConditionals = applyRules(schema, uiSchema, rules, Engine)(Form);

    return (
      <div className="row">
        <div className="col-md-6">
          <FormWithConditionals schema={schema}
                uiSchema={uiSchema}
                formData={this.state.formData}
                onChange={this.handleFormDataChange}
                noHtml5Validate={true}>
          </FormWithConditionals>
        </div>
        <div className="col-md-6">
          <FormModelInspector formData={this.state.formData}
                              showModel={this.state.showModel}
                              onChange={this.handleShowModelChange}/>
        </div>
      </div>
    );
  }
}

ConditionalForm.propTypes = {
  schema: PropTypes.object.isRequired,
  uiSchema: PropTypes.object.isRequired,
  rules: PropTypes.array.isRequired
};

ConditionalForm.defaultProps = {
  uiSchema: {},
  rules: []
};

As you can see in this demo, every time I change a field's value, the field loses focus. I suspect the cause of the problem is react-jsonschema-form-conditionals, because if I replace <FormWithConditionals> with <Form>, the problem does not occur.

If I remove the handler onChange={this.handleFormDataChange} the input field no longer loses focus when it's value changes (but removing this handler breaks the FormModelInspector).

Apologies for not providing a JSFiddle example instead of pasting all the code into the issue, but I couldn't figure out how to add react-jsonschema-form-conditionals as a dependency, and import applyRules in JSFiddle

[donalmurtagh]

The problem was caused by creating the <FormWithConditionals> in the render method. It was resolved by creating it in componentWillMount instead.