indeterminate checkbox in React JSX

问题

How do I render an indeterminate checkbox in JSX?

Here's what I've tried:

render() {
  return <input type="checkbox" 
                checked={this.props.state === "checked"} 
                indeterminate={this.props.state === "indeterminate"} />
}

However, indeterminate is not an attribute on the HTMLElement, but a property. How do I set properties from React / JSX?

回答1:

You can use the componentDidMount step (which is invoked after the initial rendering) to set that property:

componentDidMount() {
    React.findDOMNode(this).indeterminate = this.props.state === "indeterminate";
}

If you want that property to be updated with subsequent renders, do the same thing in componentDidUpdate also.

回答2:

I would probably create a composite component that encapsulates the necessary hooks to set or unset the checkbox's indeterminate property. It looks like you're using ES2015 syntax, so I'll use some of those features here.

class IndeterminateCheckbox extends React.Component {
  componentDidMount() {
    if (this.props.indeterminate === true) {
      this._setIndeterminate(true);
    }
  }

  componentDidUpdate(previousProps) {
    if (previousProps.indeterminate !== this.props.indeterminate) {
      this._setIndeterminate(this.props.indeterminate);
    }
  }

  _setIndeterminate(indeterminate) {
    const node = React.findDOMNode(this);
    node.indeterminate = indeterminate;
  }

  render() {
    const { indeterminate, type, ...props } = this.props;
    return <input type="checkbox" {...props} />;
  }
}

// elsewhere

render() {
  return <IndeterminateCheckbox
           checked={this.props.state === "checked"} 
           indeterminate={this.props.state === "indeterminate"} />
}

Working example: https://jsbin.com/hudemu/edit?js,output

回答3:

I'd suggest creating a simple component (code ported from coffeescript so mind you, might have some simple typos):

const React = require('react');

module.exports = class IndeterminateCheckbox extends React.Component {
    componentDidMount() {
        this.refs.box.indeterminate = this.props.indeterminate;
    }

    componentDidUpdate(prevProps, prevState) {
        if(prevProps.indeterminate !== this.props.indeterminate) {
            this.refs.box.indeterminate = this.props.indeterminate;
        }
    }

    render() {
        return <input {...this.props} ref="box" type="checkbox"/>;
    }

}

Now you have a simple component that behaves exactly like a checkbox, that supports the indeterminate prop. Note there's plenty of room for improvements here, namely setting propTypes and proper defaults for some props, and of course implementing componentShouldUpdate to only do something when needed.

回答4:

An alternative would be to use a ref attribute with a callback to set the property on the DOM node. For example:

render: function() {
  return (
    <input
        type="checkbox"
        ref={function(input) {
          if (input != null) {
            React.findDOMNode(input).indeterminate = this.props.indeterminate;
          }}
        {...this.props} />
  )
}

回答5:

You can also use the ref function directly:

ReactDOM.render(
  <label>
    <input
      type="checkbox"
      ref={input => {
        if (input) {
          input.indeterminate = true;
        }
      }}
    />
    {' '}
    Un test
  </label>,
  document.getElementById('root')
);

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>

回答6:

React v15 implementation:

import React from 'react';

export default class Checkbox extends React.Component {
    componentDidMount() {
        this.el.indeterminate = this.props.indeterminate;
    }

    componentDidUpdate(prevProps, prevState) {
        if(prevProps.indeterminate !== this.props.indeterminate) {
            this.el.indeterminate = this.props.indeterminate;
        }
    }

    render() {
        const {indeterminate, ...attrs} = this.props;
        return <input ref={el => {this.el = el}} type="checkbox" {...attrs}/>;
    }
}

来源：https://stackoverflow.com/questions/32139455/indeterminate-checkbox-in-react-jsx

标签

javascript

reactjs

react-jsx