state

setState inside a loop - React

由 本秂侑毒 提交于 2019-12-08 19:27:31
I am trying to build a questionnaire in react. For now, all my answers will be accepted using the textbox. These will then be sent to my api using the ajax call. I want my params to have following structure, questionnaire: { {question: "question", answer: "answer"}, {question: "question2", answer: "answer2"}, {question: "question3", answer: "answer3"} } My code so far is really messy but somehow i'm getting the desired results. However, i'm unable to update the state of my answer and keep getting the Uncaught TypeError: Cannot read property 'setState' of undefined import React, { PropTypes }

React defining state without a constructor [duplicate]

由 醉酒当歌 提交于 2019-12-08 19:20:54
问题 This question already has answers here : init state without constructor in react (3 answers) Closed 2 years ago . I've seen some react developers define state without a constructor. I like the fact that is simplifies the code, but is it safe to do so? class Dog extends React.Component { state = { sound: 'Woof' } return ( <p>Dog says { this.state.sound }</p> ) } I apologize in advance for the over simplified example. 回答1: Its exactly the same thing. Take a look at the javascript that babel

React-Native State Dynamic Color

由 我的梦境 提交于 2019-12-08 19:10:49
问题 I want to set the tintColor of my png Image dynamic. Actuall i am trying to set the color at the state properties and change them with seperate functions with the setState . My code is something like this (Expect that everything works fine above and around the following code snippet): class dynamicImageColor extends Component{ constructor(props) { super(props); this.state = { myDynamicColor: '#ffffff' } } changeColor(bool){ if(bool === true) { this.setState({ myDynamicColor: '#932727' }) }if

mapStateToProps() in Redux app nesting state within state?

由 烈酒焚心 提交于 2019-12-08 15:50:37
问题 I've hit a wall trying to figure out why the JSON data I'm fetching and storing on state isn't being mapped to my component props, yet appears when console.log() ed from within the mapStateToProps() function. Am I doing something wrong that I'm not seeing here? EDIT: Apparently the properties on state are being mapped to the component but are nested. The data property, when logged from within mapStateToProps() , has to be accessed via state.state.data . Prior to this (see reducer), when

Access state of parent component in a child component?

由 被刻印的时光 ゝ 提交于 2019-12-08 13:52:45
问题 I'm new to react js and I need to get the state of the component to be accessed by another class, I encountered this problem because I'm using atomic design because writing everything in one component is turning to be a problem, here is my code: Headcomponent : class Headcomponent extends React.Component{ constructor (props) { super(props); this.state = { email: '', password: '', formErrors: {email: '', password: ''}, emailValid: false, passwordValid: false, formValid: false, items: [], } }

How to refactor code to avoid multiple if-s [from interview]?

由 限于喜欢 提交于 2019-12-08 12:20:45
问题 On interview I was asked the following question: I have following method: public void foo(SomeObject o){ if(o.matches(constant1)){ doSomething1(); }else if(o.matches(constant2)){ doSomething2(); }else if(o.matches(constant3)){ doSomething3(); } .... } question was: you should refactor method above. What will you do? On interview I didn't grasp how to make it. Now I think that state design pattern is suitable for this task ? Am I right? What do you think? P.S. I negotiated with my colleague.

React state update step behind

由 自闭症网瘾萝莉.ら 提交于 2019-12-08 10:21:35
问题 This color picker works but one step behind. I've been using React 15.4.2. Is it an issue to be fixed in later versions? In case it's my fault, please, how to master "pending state condition"? Pen http://codepen.io/462960/pen/qrBLje Code: let Input = React.createClass({ getInitialState(){ return { today_color: "#E5D380" }; }, colorChange(e){ this.setState({ today_color: e.target.value }) document.querySelector('html').style.setProperty('--base', this.state.today_color); }, render(){ return (

Update values of edited inputs

由 筅森魡賤 提交于 2019-12-08 08:52:16
问题 I am using react-admin framework and I am trying to update values of my input dynamically. In my custom component, I have the onChange() method which looks like this: onChange = (value) => { this.setState({ currentForm: this.props.record }); const { updated_src, name, namespace, new_value, existing_value } = value; this.setState({ currentForm: updated_src }); } First I am setting that the state currentForm has the original unedited values that are stored in this.props.record . After that I am

UI-Router default view inside div

由 丶灬走出姿态 提交于 2019-12-08 07:00:44
问题 Say I have index.html with: <div ui-view="viewA"> // content </div> Is it posible to put content inside div that will serve to me as default route? So without including or anything else, just need to put some markup directly in that div. 回答1: There is a working plunker That is possible, and really pretty easy. So, let's have this inside of index.html <div ui-view=""> this is the content of ui-view, which serves as a template for a default state </div> And this could be the default state and

How to save state when preempted on a Google preemptible instance?

由 此生再无相见时 提交于 2019-12-08 03:30:28
I need to be able to save the state of a Centos-based Google Compute instance when it first receives a preemption signal. The documentation very clearly indicates that a "ACPI G2 Soft Off" signal is sent 30 seconds before a preemptible shutdown. Unfortunately, Google has given no examples to demonstrate how to capture this signal and I have not yet found a way to capture it. My initial attempts have all been focused around the ACPI Interface using the acpid daemon. Using it, I have been able to capture the shutdown (button/power) event without any problems. But no matter what event I try to
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