我正在尝试测试我的一个组件。它是来自 Material-UI 的一个 NavigationDrawer，它有一个名为 toggleDrawer() 的 prop，它可以完成这个任务并切换抽屉。
每次组件渲染时，它都会在 1ms - 2ms 的时间内调用 toggleDrawer() 函数 10 次。我很困惑为什么要这样做，并且希望尽可能解决它。
这是组件:
import React from "react";
import PropTypes from "prop-types";
import { withStyles } from "@material-ui/core/styles";
import { styles } from "../styles/NavigationDrawerStyles";
import Drawer from "@material-ui/core/Drawer";
import List from "@material-ui/core/List";
import ListItem from "@material-ui/core/ListItem";
import ListItemText from "@material-ui/core/ListItemText";
import ListItemIcon from "@material-ui/core/ListItemIcon";
import Collapse from "@material-ui/core/Collapse";
import ExpandLess from "@material-ui/icons/ExpandLess";
import ExpandMore from "@material-ui/icons/ExpandMore";
import ViewListIcon from "@material-ui/icons/ViewListOutlined";
import CreateOutlinedIcon from "@material-ui/icons/CreateOutlined";
import ShuffleIcon from "@material-ui/icons/Shuffle";
import ChevronLeftIcon from "@material-ui/icons/ChevronLeft";
import HomeIcon from "@material-ui/icons/HomeOutlined";
import ContactsIcon from "@material-ui/icons/ContactsOutlined";
import BusinessIcon from "@material-ui/icons/BusinessOutlined";
import IconButton from "@material-ui/core/IconButton";
import DescriptionIcon from "@material-ui/icons/DescriptionOutlined";
import DashboardOutlinedIcon from "@material-ui/icons/DashboardOutlined";
import BookOutlinedIcon from "@material-ui/icons/BookOutlined";
import Divider from "@material-ui/core/Divider";
import { Link } from "react-router-dom";
class NavigationDrawer extends React.Component {
constructor(props) {
super(props);
this.state = {
postsOpen: false,
policiesOpen: false
};
}
handlePostsClick = () => {
this.setState(state => ({ postsOpen: !state.postsOpen }));
};
handlePoliciesClick = () => {
this.setState(state => ({ policiesOpen: !state.policiesOpen }));
};
render() {
const { classes, toggleDrawer, open } = this.props;
const { postsOpen, policiesOpen } = this.state;
return (
<React.Fragment>
<Drawer
open={open}
onClose={toggleDrawer(false)}
className={classes.drawerPaper}
>
<div
tabIndex={0}
role="button"
//onClick={toggleDrawer(false)}
//onKeyDown={toggleDrawer(false)}
className={classes.list}
>
<div className={classes.drawerHeader}>
<IconButton
className={classes.CloseIcon}
onClick={toggleDrawer(false)}
>
<ChevronLeftIcon />
</IconButton>
</div>
<Divider />
<List>
<ListItem
button
component={Link}
to="/"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<HomeIcon />
</ListItemIcon>
<ListItemText inset primary="Home" />
</ListItem>
<ListItem button onClick={this.handlePostsClick}>
<ListItemIcon>
<DashboardOutlinedIcon />
</ListItemIcon>
<ListItemText inset primary="Posts" />
{postsOpen ? <ExpandLess /> : <ExpandMore />}
</ListItem>
<Collapse in={postsOpen} timeout="auto" unmountOnExit>
<List component="div" disablePadding>
<ListItem
button
className={classes.nested}
id="posts-nested-dropdown"
component={Link}
to="/posts/"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<ViewListIcon />
</ListItemIcon>
<ListItemText inset primary="Recent Posts" />
</ListItem>
<ListItem
button
className={classes.nested}
component={Link}
to="/posts/create/"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<CreateOutlinedIcon />
</ListItemIcon>
<ListItemText inset primary="Create a Post" />
</ListItem>
<ListItem button className={classes.nested}>
<ListItemIcon>
<ShuffleIcon />
</ListItemIcon>
<ListItemText inset primary="Random Post" />
</ListItem>
</List>
</Collapse>
<ListItem
button
component={Link}
to="/about"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<BusinessIcon />
</ListItemIcon>
<ListItemText inset primary="About" />
</ListItem>
<ListItem
button
component={Link}
to="/contact"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<ContactsIcon />
</ListItemIcon>
<ListItemText inset primary="Contact" />
</ListItem>
<ListItem
button
component="a"
href="http://docs.chbresser.com"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<DescriptionIcon />
</ListItemIcon>
<ListItemText inset primary="Docs" />
</ListItem>
<Divider />
<ListItem button onClick={this.handlePoliciesClick}>
<ListItemIcon>
<BookOutlinedIcon />
</ListItemIcon>
<ListItemText inset primary="Important Policies" />
{policiesOpen ? <ExpandLess /> : <ExpandMore />}
</ListItem>
<Collapse in={policiesOpen} timeout="auto" unmountOnExit>
<List component="div" disablePadding>
<ListItem
button
className={classes.nested}
component={Link}
to="/privacy/"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<ViewListIcon />
</ListItemIcon>
<ListItemText inset primary="Privacy Policy" />
</ListItem>
<ListItem
button
className={classes.nested}
component={Link}
to="/terms/"
onClick={toggleDrawer(false)}
>
<ListItemIcon>
<ViewListIcon />
</ListItemIcon>
<ListItemText inset primary="Terms and Conditions" />
</ListItem>
</List>
</Collapse>
</List>
<div className={classes.drawerFooter}>
<i
className={`fas fa-hand-holding-heart ${classes.footerIcon}`}
/>{" "}
Made with love by the TechHorizon team.
<br />
</div>
</div>
</Drawer>
</React.Fragment>
);
}
}
NavigationDrawer.propTypes = {
classes: PropTypes.object.isRequired,
toggleDrawer: PropTypes.func.isRequired
};
export default withStyles(styles)(NavigationDrawer);
这是我迄今为止的测试:
import { createShallow } from "@material-ui/core/test-utils";
import React from "react";
import NavigationDrawer from "../components/NavigationDrawer";
import "jest-dom/extend-expect";
const toggleDrawer = jest.fn();
describe("<NavigationDrawer />", () => {
let shallow;
beforeEach(() => {
shallow = createShallow({ dive: true });
});
it("renders a Drawer", () => {
const page = shallow(<NavigationDrawer toggleDrawer={toggleDrawer} />);
expect(toggleDrawer.mock.calls.length).toEqual(0);
expect(page.find("WithStyles(Drawer)").length).toEqual(1);
});
it("renders the main List and 2 dropdown Lists", () => {
const page = shallow(<NavigationDrawer toggleDrawer={toggleDrawer} />);
expect(page.find("WithStyles(List)").length).toEqual(3);
});
it("opens posts menu on click", () => {
const page = shallow(<NavigationDrawer toggleDrawer={toggleDrawer} />);
expect(toggleDrawer.mock.calls.length).toEqual(1);
});
});
每个测试都会调用 toggleDrawer() 10 次。
最佳答案
这行是你的问题(并且重复了 10 次):
onClick={toggleDrawer(false)}
而不是将带有此参数的函数传递给 ListItem 的 props ，这调用 toggleDrawer(false)并将该函数调用的结果作为 prop 传递。
如果你想要toggleDrawer()使用参数 false 调用当 onClick事件被触发，您应该将其包装在如下函数中:
onClick={() => toggleDrawer(false)}
或者，您可以使用 Function.prototype.bind() 像这样:
onClick={toggleDrawer.bind(this, false)}
这两个都被列为推荐选项 in the React docs .
<小时/>此行为是notably different从如何在纯 HTML 中附加事件处理程序:
HTML: <div onclick="handleEvent()" />
JSX: <div onClick={handleEvent} />
关于javascript - 组件每次渲染调用函数10次，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/53783676/