classNames('foo', 'bar'); // => 'foo bar' classNames('foo', { bar: true }); // => 'foo bar' classNames({ 'foo-bar': true }); // => 'foo-bar' classNames({ 'foo-bar': false }); // => '' classNames({ foo: true }, { bar: true }); // => 'foo bar' classNames({ foo: true, bar: true }); // => 'foo bar' 

let buttonType = 'primary';
classNames({ [`btn-${buttonType}`]: true }); 

var Button = React.createClass({ // ... render () { var btnClass = 'btn'; //根据点击的state来控制css if (this.state.isPressed) btnClass += ' btn-pressed'; else if (this.state.isHovered) btnClass += ' btn-over'; return <button className={btnClass}>{this.props.label}</button>; } }); 

var classNames = require('classnames'); var Button = React.createClass({ // ... render () { var btnClass = classNames({ 'btn': true, 'btn-pressed': this.state.isPressed, 'btn-over': !this.state.isPressed && this.state.isHovered }); return <button className={btnClass}>{this.props.label}</button>; } }); 

var classNames = require('classnames/bind'); var styles = { foo: 'abc', bar: 'def', baz: 'xyz' }; var cx = classNames.bind(styles); var className = cx('foo', ['bar'], { baz: true }); // => "abc def xyz" 

/* components/submit-button.js */
import { Component } from 'react'; import classNames from 'classnames/bind'; import styles from './submit-button.css'; let cx = classNames.bind(styles); export default class SubmitButton extends Component { render () { let text = this.props.store.submissionInProgress ? 'Processing...' : 'Submit';//text根据状态来动态加载 let className = cx({ base: true, inProgress: this.props.store.submissionInProgress,//样式的动态加载 error: this.props.store.errorOccurred, disabled: this.props.form.valid, }); return <button className={className}>{text}</button>; } };