Question

我试图在ngOnit内调用trimObj但是抛出错误，当你使用typescript中的angular2函数时，什么是正确的实现。打字稿新手我会很感激帮助。

app.component.ts

    export class StreamComponent implements OnInit {
        displayedColumns = ['ticketNum', "assetID", "severity", "riskIndex", "riskValue", "ticketOpened", "lastModifiedDate", "eventType"];
        dataSource: MatTableDataSource<Element[]>;
        socket = io();
        constructor(private streamService: StreamService) {};
        ngOnInit() {
        this.socket.on('newMessage', (event) => {
                         console.log('New Event', event);
                          let data = trimObj(event);
                          this.dataSource.data.push(data);
                           this.dataSource.data = [...this.dataSource.data]
                          console.log("DATA",this.dataSource.filteredData);
                       });
                });
        }
        trimObj(obj) => {
              var neededKeys = ['ticketNum', "assetID", "severity", "riskIndex", "riskValue", "ticketOpened", "lastModifiedDate", "eventType"];
              var newObj = {};
              neededKeys.forEach(function (key) {
                newObj[key] = obj[key];
              });
              return newObj;
            }
    }

export interface Element {
    ticketNum: number;
    ticketOpened: number;
    eventType: string;
    riskIndex: string;
    riskValue: number;
    severity: string;
    lastModifiedDate: number;
    assetID: string;
}

错误

ERROR in app.component.ts(29,17): error TS1144: '{' or ';' expected.
app.component.ts(29,20): error TS1068: Unexpected token. A constructor, method, accessor, or property was expected.
app.component.ts(38,1): error TS1128: Declaration or statement expected.

Answer 1

只需使用此

进行调用即可

this.trimObj(event);

您实际上还有其他语法问题。这是您更正后的代码：

export class StreamComponent implements OnInit {
    displayedColumns = [
        'ticketNum',
        'assetID',
        'severity',
        'riskIndex',
        'riskValue',
        'ticketOpened',
        'lastModifiedDate',
        'eventType'
    ];

    dataSource: MatTableDataSource<Element[]>;

    socket = io();

    constructor(private streamService: StreamService) {}

    ngOnInit() {
        this.socket.on('newMessage', event => {
            console.log('New Event', event);
            const data = this.trimObj(event);
            this.dataSource.data.push(data);
            this.dataSource.data = [...this.dataSource.data];
            console.log('DATA', this.dataSource.filteredData);
        });
    }

    trimObj(obj): Element {
        const neededKeys = [
            'ticketNum',
            'assetID',
            'severity',
            'riskIndex',
            'riskValue',
            'ticketOpened',
            'lastModifiedDate',
            'eventType'
        ];
        const newObj: Element = <any>{};
        neededKeys.forEach(function(key) {
            newObj[key] = obj[key];
        });
        return newObj;
    }
}

Answer 2

您正在将trimObj定义为类方法...您还尝试将其内联定义为箭头函数，这是一种语法错误。

实际上有一些语法错误 - 也删除了额外的});。

有几种解决方案：

用作类方法。

let data = this.trimObj(event);
...
trimObj(obj) {

删除=>，因为这会导致语法错误。现在，trimObj已正确定义为类方法，您可以使用this.trimObj()调用它。

用作单独的功能

由于trimObj与StreamComponent类没有特定关系，并且是一个实用程序函数，您可以单独定义它，也可以在自己的文件中定义：

export function trimObj(obj) {

然后在StreamComponent import { trimObj } from './utilties'您可以trimObj()（如果在同一文件中定义则无需导入），并使用@SpringBootApplication public class MyApplication implements ApplicationListener<ApplicationEnvironmentPreparedEvent> { private static final Logger LOGGER = LoggerFactory.getLogger(MyApplication.class); public static void main(String[] args) { new SpringApplicationBuilder() .listeners(new MyApplication()) .sources(MyApplication.class) .run(args); } @Override public void onApplicationEvent(final ApplicationEnvironmentPreparedEvent event) { if (event.getEnvironment().getActiveProfiles().length == 0) { LOGGER.error("No active profile is set. Will terminate"); System.exit(1); } } }进行调用。

如何使用打字稿调用angular2中的函数？

2 个答案:

用作类方法。

用作单独的功能