小编Leo*_*ban的帖子

我有.tag一个以点击/ mousedown操作命名的几个类,我想要更改clear:both为clear:none所有.tag项目.或者将类添加.clearNone { clear:none; }到所有标记中.

到目前为止我没有运气的尝试:

function mouseDown(e) {
    window.addEventListener('mousemove', sizePanel, true);

    // Using ID works
    var tagsCol = document.getElementById("tags-col");
    tagsCol.classList.add("width100");

    // Using class does not
    var tag = document.getElementsByClassName("tag");
    tag.classList.add("clearNone");
};

CSS

.tag {
    overflow: hidden;
    float: left;
    position: relative;
    margin: 0 10px 10px 0;
    padding: 5px 10px;
    width: auto;
    cursor: pointer;
    clear: both;
    @include rounded(4px);
}

.clearNone  { clear: none; }

你会怎么做到这一点？注意,有上百.tag的

显然tagObjects是一个数组,长度为0.但是它仍然经过检查并导致错误.

TypeError:无法读取未定义的属性"length"

if (tagObjects != "empty" || tagObjects.length === 0) {
    for (var i = 0; i < tagObjects.tags.length; i++) {
        temp_tags.push(tagObjects[i].tags);
    }

    temp_tags.forEach(function(obj) {
        if (obj.selected) {
            if (vs.tags[map[obj.term]] != undefined) {
                vs.tags[map[obj.term]].selected = true;
            }
        }
    });
}

它甚至超过了字符串检查!

我创建了一个生成并返回对象的函数:

function TickersObj(tag, array, boolLots, boolOptions, boolDisplay) {
    tag         = tag         || {};
    array       = array       || [];
    boolLots    = boolLots    || false;
    boolOptions = boolOptions || false;
    boolDisplay = boolDisplay || true;

    console.log('tag = ', tag);
    console.log('array = ', array);
    console.log('boolLots = ', boolLots);
    console.log('boolOptions = ', boolOptions);
    console.log('boolDisplay = ', boolDisplay);

    this.assoTikArray     = array;
    this.lotsOfTags       = boolLots;
    this.tagOptions       = boolOptions;
    this.tagsHoverDisplay = boolDisplay;
    return this;
}

稍后在我的代码中我传递的值如下:

switch(type) {
    case 'tagsPanel':
        tag.tickers  = data.data.ticker_tag.tickers;
        var tickersObj = TickersObj(tag, …

http://codepen.io/leongaban/pen/xwwdXr?editors=101

我有一个返回Object的API,如下所示:

{ unsure: 5, products: 25, trend: 124 }

我需要做的是获取这些键/值对并将它们添加到数组中,以便它们如下所示:

catArray = [
    { unsure: 5 },
    { products: 5 },
    { trend: 5 },
]

更好的是:

catArray = [
    {
        name: unsure,
        count: 5
    },
    {
        name: products,
        count: 15
    },
    {
        name: trend,
        count: 50
    }
]

当前的代码集代码:

var categories = { unsure: 5, products: 25, trend: 124 }
var catArray   = [];

for (var i in categories) {
  console.log(i + ":" + categories[i]);
  catArray[i] = categories[i]; …

基本上,我想知道在用户点击时在两个img或div之间切换的最佳方法.因此,首先播放图像是可见的,当用户点击时,隐藏播放图像并显示暂停图像.当用户点击暂停图像时,隐藏暂停图像并显示播放图像.

我尝试使用ng-show但我只能弄清楚如何显示两个图像而不隐藏另一个.因此,播放图像将在暂停图像旁边,这是不理想的.

提前致谢 :)

我试过的代码不起作用:

HTML

<button ng-click="changeStatus" ng-show="checkStatus">Play</button>
<button ng-click="changeStatusAgain" ng-hide="checkStatus">Pause</button>

控制器:

$scope.changeStatus=function(){
    $scope.checkStatus = false;
}

$scope.changeStatusAgain=function(){
    $scope.checkStatus = true;
}

https://jsfiddle.net/n8nnwtte/

在我的index.js中,addCoin操作正在运行.

import { addCoin } from './reducer/portfolio/actions'

const element = document.getElementById('coinhover');

const store = createStore(reducer, compose(
    applyMiddleware(thunk),
    window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__()
));

store.dispatch(addCoin('bitcoin'));

在store.dispatch调用时,我可以在这里看到更新的状态.

但是,我不想从我的index.js调用调度操作,而是从我的组件中调用.

我的SearchCoin组件:

import React from 'react'
import { connect } from 'react-redux'
import * as R from 'ramda'
import * as api from '../../services/api'
import { addToPortfolio, findCoins } from '../../services/coinFactory'
import { addCoin } from '../../reducer/portfolio/actions'

const mapDispatchToProps = (dispatch) => ({
    selectCoin(coin) {
        return () => {
            dispatch(addCoin(coin))
        } …

所以刚刚学会了componentWillReceiveProps已弃用,我们现在需要使用getDerivedStateFromProps生命周期方法. https://reactjs.org/docs/react-component.html#static-getderivedstatefromprops

我在下面使用它:

class Main extends Component {
  static getDerivedStateFromProps(props) {
    console.log('getDerivedStateFromProps', props);
    const { modal } = props;
    this.setState({ modal });
  }

  constructor(props) {
    super(props);

    this.state = {
      modal: {}
    };
  }

但是它出错了 setState

main.js:30未捕获的TypeError:无法在getDerivedStateFromProps(main.js:30)读取null的属性'setState'

我在这里错过了什么？

在我的 React/NextJS 应用程序中，我有这个简单的输入：

成分：

搜索 > 搜索选择 > ExchangeInfo.tsx：

搜索.tsx

<SearchSelect
  assets={assets}
  selected={selected}
  exchange={exchange}
  exchanges={exchanges}
  fetching={fetching}
  aggregate={aggregate}
  checkAggregate={this.handleCheckAggregate}
  enterPosition={this.handleEnterPosition}
  exchangeSelect={this.handleExchangeSelect}
/>

//... the function:

@bind
handleEnterPosition(position: number) {
  this.setState({ position })
}

搜索选择

<SearchExchanges
  selected={selected}
  exchange={exchange}
  exchanges={exchanges}
  checkAggregate={checkAggregate}
  aggregate={aggregate}
  enterPosition={this.props.enterPosition}
  exchangeSelect={this.props.exchangeSelect}
/>

交换信息

import React from 'react'
import { bind } from 'decko'

import { IAsset, IMarketAsset } from '../../shared/types'
import { EnterPositionStyle } from '../../styles'

interface IPropsInfo {
  asset: IAsset
}

interface IPropsCount {
  exchanges: IMarketAsset[]
}

interface IPropsPosition …

我有从 redux 中提取的事件，如果events数组包含数据，updateData则将用于将事件过滤到状态 var 中data。

我已经data和events都添加到了这里提到的依赖数组中。但我仍然收到此错误：

const SingleTable = () => {
    const events = useSelector(state => eventsSelector(state));
    const [data, updateData] = useState([]);
    const [sortCol, updateSortCol] = useState(0);
    const [sortDir, updateSortDir] = useState('ascending');

    useEffect(() => {
        const formattedArray = events ? formatLoss(events): [];

        events && updateData(formattedArray);
    }, [data, events]);

    //...

想法，想法？

在我的组件中，我有一个名为 AuthForm 的函数，它使用一个开关来渲染 3 个组件中的 1 个。在方法参数中，我传入了一个类方法数组。除了如何正确键入类方法本身之外，我已经记录了所有类型。

错误：

（别名）接口 ISignInData

导入ISignInData

声明类型既不是“void”也不是“any”的函数必须返回一个值。ts(2355)

首先是接口和类型

export interface ISignInData {
  email: string
  password: string
}

export interface IAccountData {
  email: string
  password: string
  password2: string
}

export interface IForgotData {
  email: string
}

export type TSignIn = (email: string, password: string) => (ISignInData)

export type TCreateAccount = (email: string, password: string, password2: string) => (IAccountData)

export type TForgot = (email: string) => (IForgotData)

组件

import React from 'react'

import { Astronaut, Login, Create, …

http://jsfiddle.net/leongaban/BvuT5/

试图让第二个警报弹出两次,但似乎for循环甚至没有运行.

jQuery的

var wireRequestorCard = function(jarjar) {

    alert('1st alert');

    var loop_num = 0;
    for (var i = 0, length = jarjar.length; i < length; i++) {
        loop_num = i;
        alert('Where is this Alert? '+i);
        }

    alert('Closing Alert');
    }

var jarjar = 2;

wireRequestorCard(jarjar);

我试图在金字塔中获得以下数组的长度.

当我在下面尝试这个

${outbox_details.details['declined']} 
${outbox_details.details['accepted']}
${outbox_details.details['pending']}

我看到我认为在HTML中生成的空数组:

上面的完整标记:

<li>
    <img src="..." alt="Denied"/>${outbox_details.details['declined']} denied
</li>
<li>
    <img src="..." alt="Accepted"/>${outbox_details.details['accepted']} accepted
</li>
<li>
    <img src="..." alt="Pending"/>${outbox_details.details['pending']} pending
</li>

我试过.length和.len,但是他们都在PyCharm中出错了:

${outbox_details.details.length.(['declined'])} 
${outbox_details.details.len['declined']}
${outbox_details.details.len(['declined'])} 

如果您是Python或后端开发人员,您将如何获得已接受,已拒绝或待定数组的长度？