小编pra*_* vv的帖子

我正在尝试在我的电脑上安装 Angular 5。一切都安装正确，但是当我使用“ng-serve”命令运行我的应用程序时，它显示以下错误。

You are running version v8.7.0 of Node.js, which is not supported by Angular CLI v6.
The official Node.js version that is supported is 8.9 and greater.

Please visit https://nodejs.org/en/ to find instructions on how to update Node.js.

Node.js 的当前版本是“8.7.0”，npm 是“6.0.0”。

经过大量搜索后，我按照以下步骤在 Windows 10 上更新我的 Node.js

npm cache clean -f
npm install -g n
n latest

但我无法使用此命令，它显示以下错误

C:\WINDOWS\system32>npm cache clean -f
npm WARN using --force I sure hope you know what you are doing.

C:\WINDOWS\system32>npm install -g n …

我试图在这个链接的帮助下在角度6中做ssr ,但它显示以下错误

Node server listening on http://localhost:4000
TypeError: StaticInjectorError[InjectionToken Application Initializer -> InjectionToken DocumentToken]:
  StaticInjectorError(Platform: core)[InjectionToken Application Initializer -> InjectionToken DocumentToken]:
    Right-hand side of 'instanceof' is not an object

server.ts

// These are important and needed before anything else
import 'zone.js/dist/zone-node';
import 'reflect-metadata';

import { renderModuleFactory } from '@angular/platform-server';
import { enableProdMode } from '@angular/core';

import * as express from 'express';
import { join } from 'path';
import { readFileSync } from 'fs';

// Faster server renders w/ …

我目前在这个问题上花了一天时间,仍然无法从角度5的网址下载文件

leadGenSubmit() {

    return this.http.get('http://kmmc.in/wp-content/uploads/2014/01/lesson2.pdf',
    {responseType:ResponseContentType.Blob}).subscribe((data)=>{
        console.log(data);
        var blob = new Blob([data], {type: 'application/pdf'});
        console.log(blob);
        saveAs(blob, "testData.pdf");
    },
    err=>{
        console.log(err);
        }
    )
}

当我运行上面的代码时,它显示以下错误

ERROR TypeError: req.responseType.toLowerCase is not a function
    at Observable.eval [as _subscribe] (http.js:2187)
    at Observable._trySubscribe (Observable.js:172)

如何解决这个问题.任何人都可以发布正确的代码从角度5的网址下载pdf文件？

我在我的angular6应用程序中使用rxjs6间隔。以下是我在angular6应用程序中实现间隔的代码。

app.component.ts

import { interval } from 'rxjs/observable/interval';
const source = interval(1000);
const subscribe = source.subscribe(val => console.log(val));

一切正常，但是如何停止这个间隔？当我尝试取消订阅angular时说 source.unsubscribe is not a function

我正在尝试使用angular 6做简单的redux应用程序。

减速器

import { login,logout } from '../actions/actions';
export interface appReducer {
    login:boolean,
    user:String
}
const initialstate:appReducer={
    login:false,
    user:'guest'
}
export function reducer(state=initialstate,action):appReducer {
    switch(action.type) {
        case login:
            return {...state,login:true,user:action.payload}
        case logout:
            return {...state,login:false,user:action.payload}   
    }
    return state;
}

动作

export const login="LOGIN";
export const logout="LOGOUT"

索引

import { reducer,appReducer } from './reducer';
import { ActionReducerMap }  from '@ngrx/store';
interface appState {
    appReducer:appReducer;
}
export const reducers:ActionReducerMap<appState>= {
    appReducer:reducer
}

records.service.ts

import { Injectable } from '@angular/core';
import { HttpClient,HttpHeaders …

我有一个父视图容器，它包含另一个具有两个按钮组件的视图。我需要在按钮组件之间留出一个空间，因为我将 justify-content 添加到子视图容器中，但它不起作用。

代码

import React,{Component} from 'react';
import { View,Image,StyleSheet,Dimensions } from 'react-native';
import { Card,Button,Avatar } from 'react-native-elements';
import Icon from 'react-native-vector-icons/FontAwesome';
export default class WelcomePage extends Component {
    render() {
        const {navigate}=this.props.navigation
        return (
            <View style={{flexDirection:'column',flex:1,alignItems:'center',justifyContent: 'flex-start'}}>
            <Avatar
              width={Dimensions.get('window').width}
              containerStyle={{flex:85}}
              avatarStyle={{flex:85}}
              imageProps={{resizeMode:'cover'}}
              source={require('../assets/images/logo.png')}
              onPress={() => console.log("Works!")}
              activeOpacity={0.7}
            />
            <View style={{flexDirection:'row',flex:15,marginTop:10,justifyContent:'space-between'}}>
                <Button  large title='LOGIN' icon={<Icon name="user-secret" size={25} color="white" />} buttonStyle={{height:50,width:130,backgroundColor:"#b3b3b3"}} titleStyle={{fontWeight:"700"}} containerViewStyle={{borderRadius:5}} borderRadius={5} />
                <Button  large title='REGISTER'  icon={<Icon name="user-plus" size={25} color="white" />} buttonStyle={{height:50,width:130,backgroundColor:"#b3b3b3"}} titleStyle={{fontWeight:"700"}} onPress={() => navigate('register')} containerViewStyle={{borderRadius:5}} …

我试图通过遵循此链接来创建角度为6的通用应用程序。完成链接中提到的步骤后，我尝试构建通用应用程序，但显示以下错误。

Project 'testapp' could not be found in workspace.
Error: Project 'testapp' could not be found in workspace.

谁能帮我解决这个问题？

我正在使用redux和react-redux来改变我的应用程序的状态.

我有两个组件,Login和Home.

如果用户正确登录并导航到Home组件,我将调度一个动作来更新状态.我在Home组件路径中使用authguard 来检查用户是否已记录.

但是当我Home通过在地址栏中键入路由导航到组件时,页面将刷新,状态将更改为其初始值.

即使使用地址栏导航到组件,如何维护状态值？

我是 react-native 的新手，我正在尝试使用 react-native 元素 1.00 beta4 中的所有输入组件创建一个简单的页面。我的问题是即使父视图 flexdirection 在 'row '。

注册.js

import React,{ Component } from 'react';
import { Field,reduxForm } from 'redux-form';
import { View,Button } from 'react-native';
import {Icon,CheckBox,Text,Input} from 'react-native-elements';
 const renderField=({label,keyboardType,name,icon,iconType}) => {
    return(
            <View style={{flexDirection:'row'}}>
                <Input placeholder={label} inputContainerStyle={{borderWidth:2,borderColor:'lightgrey',borderRadius:20}} inputStyle={{color:'grey'}} leftIcon={<Icon size={25} type={iconType} name={icon} color="grey" />} errorStyle={{fontSize:15}} errorMessage="error" />
            </View>
    )
}
 const checkBoxField=({label,keyboardType,name}) => {
    return(
            <View style={{flexDirection:'row'}}>
                <Text>{label}</Text>
                <CheckBox  title='Male' checkedIcon='dot-circle-o' uncheckedIcon='circle-o' checked={true} containerStyle={{backgroundColor:'transparent'}} />      
            </View>
    )
}

const RegisterForm=props => { …