import React, { Component } from "react";
import { FormattedMessage } from "react-intl";
import { connect } from "react-redux";

class Project extends Component {
  render() {
    return (
      <div
        className={
          "ih-item square effect6 from_top_and_bottom grid-item " +
          this.props.category +
          " " +
          this.props.widthClass
        }
      >
        <FormattedMessage id="route.project">
          {route => {
            return (
              <a href={"/" + route + this.props.url}>
                <div className="img">
                  <img src={this.props.mainImage} alt="img" />
                </div>
                <div className="info">
                  <h3>{this.props.header}</h3>
                  <p>{this.props.description}</p>
                </div>
              </a>
            );
          }}
        </FormattedMessage>
      </div>
    );
  }
}

const mapStateToProps = state => {
  return {
    projects: state.project.projects
  };
};

export default connect(
  mapStateToProps,
  {}
)(Project);

回答如下：

我想你需要安装react-router-dom。其次，请使用template strings。