小编aas*_*dar的帖子

我在用

• Angular CLI:6.0.5
• 节点:8.11.1
• 角度:6.0.3
• rxjs:6.2.0

在编译Angular 6应用程序时,我遇到了错误,下面只是第一个

ERROR in ./src/app/web.service.ts
Module not found: Error: Can't resolve 'rxjs/add/operator/toPromise' in 
'C:\Node\ang\frontend\src\app'

我的web.service.ts代码

import { Http, Headers, Response } from '@angular/http';
import 'rxjs/add/operator/toPromise';

export class WebService{
    constructor(private http:Http){

    }
    getMessages(){
        return this.http.get("http://localhost:2000/messages").toPromise(); 
    }
} 

我的app.module.ts代码

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import {NoopAnimationsModule} from '@angular/platform-browser/animations';
import {MatButtonModule,
  MatCardModule,
  MatSnackBarModule,
  MatToolbarModule,
  MatInputModule} from '@angular/material';

import { AppComponent } from './app.component';
import { WebService …

要求： 我如何转换以下 json 格式。

从 ：

[
{"u0":{"user_id":"124", "name":"Eloise R. Morton"}},
{"u1":{"user_id":"126", "name":"Mary S. Williams"}}
]

到 ：

 {
 "u0":{"user_id":"124", "name":"Eloise R. Morton"},
 "u1":{"user_id":"126", "name":"Mary S. Williams"}
 }

我想从 JSON 中删除/删除第一个和最后一个方括号。

PHP代码：

$sql = "SELECT * FROM user_list";
$result = $conn->query($sql);
$user_count=0;
if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        $user_count_id="u".$user_count;
        $user_count++;
        $user_list[]=   array($user_count_id=>$row);
    }
} else {
    echo "0 results";
}
echo json_encode($user_list);
$conn->close();

Javascript代码：

function update_user_list(){
    //Fetch data
        $.ajax( "user_list.php" ).done(function(json) …

I am trying to change the default pie chart color. but all 3 pie chart arc showing red color. Apply the first color in pieColor array to all arc. I am using chart.js 2.9.3, ng2-charts 2.3.0 & angular 8. Also, I am trying a different color format like hex code or RGB but not working.

pie-chart.component.html

<div class="chart-wrapper">
    <canvas baseChart 
    [data]="doughnutChartData"
    [labels]="doughnutChartLabels"
    [colors]="pieColor
    [chartType]="doughnutChartType">
  </canvas>
</div>

pie-chart.component.ts

import { Component } from '@angular/core';
import { ChartType } from 'chart.js';
import …