redash/client/app/components/CodeBlock.jsx

import React from 'react';
import PropTypes from 'prop-types';
import Button from 'antd/lib/button';
import Tooltip from 'antd/lib/tooltip';
import './CodeBlock.less';

export default class CodeBlock extends React.Component {
  static propTypes = {
    copyable: PropTypes.bool,
    children: PropTypes.node,
  };

  static defaultProps = {
    copyable: false,
    children: null,
  };

  state = { copied: null };

  constructor(props) {
    super(props);
    this.ref = React.createRef();
    this.copyFeatureEnabled = props.copyable && document.queryCommandSupported('copy');
    this.resetCopyState = null;
  }

  componentWillUnmount() {
    if (this.resetCopyState) {
      clearTimeout(this.resetCopyState);
    }
  }

  copy = () => {
    // select text
    window.getSelection().selectAllChildren(this.ref.current);

    // copy
    try {
      const success = document.execCommand('copy');
      if (!success) {
        throw new Error();
      }
      this.setState({ copied: 'Copied!' });
    } catch (err) {
      this.setState({
        copied: 'Copy failed',
      });
    }

    // reset selection
    window.getSelection().removeAllRanges();

    // reset tooltip
    this.resetCopyState = setTimeout(() => this.setState({ copied: null }), 2000);
  };

  render() {
    const { copyable, children, ...props } = this.props;

    const copyButton = (
      <Tooltip title={this.state.copied || 'Copy'}>
        <Button
          icon="copy"
          type="dashed"
          size="small"
          onClick={this.copy}
        />
      </Tooltip>
    );

    return (
      <div className="code-block">
        <code {...props} ref={this.ref}>
          {children}
        </code>
        {this.copyFeatureEnabled && copyButton}
      </div>
    );
  }
}