[英]Keeping console.log() line numbers in a wrapper function in TypeScript / Angular 2
[英]How to write console.log wrapper for Angular2 in Typescript?
有没有办法编写一个全局自制的mylogger函数,我可以在Angular2 typescript项目中使用我的服务或组件而不是console.log函数?
我想要的结果是这样的:
mylogger.ts
function mylogger(msg){
console.log(msg);
};
user.service.ts
import 'commons/mylogger';
export class UserService{
loadUserData(){
mylogger('About to get something');
return 'something';
};
};
您可以将其编写为服务,然后使用依赖注入使该类可用于您的组件。
import {Injectable, provide} from 'angular2/core';
// do whatever you want for logging here, add methods for log levels etc.
@Injectable()
export class MyLogger {
public log(logMsg:string) {
console.log(logMsg);
}
}
export var LOGGING_PROVIDERS:Provider[] = [
provide(MyLogger, {useClass: MyLogger}),
];
您可以通过将其添加到bootstrap
的providers数组中,将其放在应用程序的顶级注入器中。
import {LOGGING_PROVIDERS} from './mylogger';
bootstrap(App, [LOGGING_PROVIDERS])
.catch(err => console.error(err));
这里有一个非常简单的例子: http : //plnkr.co/edit/7qnBU2HFAGgGxkULuZCz?p = preview
接受的答案给出的示例将从记录器类MyLogger
打印日志,而不是从实际记录的类中打印日志。
我修改了提供的示例,以便从调用MyLogger.log()
的确切行中获取日志,例如:
get debug() {
return console.debug.bind(console);
}
get log() {
return console.log.bind(console);
}
我在这里找到了如何做到这一点: https : //github.com/angular/angular/issues/5458
Plunker: http ://plnkr.co/edit/0ldN08?p = preview
根据developers.mozilla中的文档,
The bind() method creates a new function that, when called, has its
this keyword set to the provided value, with a given sequence of
arguments preceding any provided when the new function is called.
有关bind
更多信息:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind
如果要在组件中使用“console.log”功能,可以执行以下操作:
import { Component, OnInit } from '@angular/core';
var output = console.log;
@Component({
selector: 'app-component',
templateUrl: './app.component.html',
styleUrls: ['./app.component.scss']
})
export class AppComponent implements OnInit {
constructor() { }
ngOnInit() { }
printFunction(term: string): void {
output('foo');
}
}
如何在主服务上使用控制台,所以我们可以有条件地自定义和应用console.log
:
myComponent.ts
export class myComponent implements OnInit {
constructor(
private config: GlobalService
) {}
ngOnInit() {
this.config.log('func name',{a:'aval'},'three');
}
}
global.service.ts
@Injectable()
export class GlobalService {
constructor() { }
this.prod = true;
public log(one: any, two?: any, three?: any, four?: any) {
if (!this.prod) {
console.log('%c'+one, 'background:red;color:#fff', two, three, four);
}
}
}
(注意:在这个例子中,第一个参数应该是字符串);
用于切换console.log ON \\ OFF:
logger.service.ts:
import { Injectable } from '@angular/core';
@Injectable()
export class LoggerService {
private oldConsoleLog = null;
enableLogger(){
if (this.oldConsoleLog == null) { return; }
window['console']['log'] = this.oldConsoleLog;
}
disableLogger() {
this.oldConsoleLog = console.log;
window['console']['log'] = function () { };
};
}
app.component.ts:
@Component({
selector: 'my-app',
template: `your templ;ate`
})
export class AppComponent {
constructor(private loggerService: LoggerService) {
var IS_PRODUCTION = true;
if ( IS_PRODUCTION ) {
console.log("LOGGER IS DISABBLED!!!");
loggerService.disableLogger();
}
}
}
我在这里根据提供的信息创建了一个记录器
它目前非常基本(hacky :-)),但它保留了行号
@Injectable()
export class LoggerProvider {
constructor() {
//inject what ever you want here
}
public getLogger(name: string) {
return {
get log() {
//Transform the arguments
//Color output as an example
let msg = '%c[' + name + ']';
for (let i = 0; i < arguments.length; i++) {
msg += arguments[i]
}
return console.log.bind(console, msg, 'color:blue');
}
}
}
}
希望这可以帮助
类型更安全(ish)版本,角度为4,打字稿2.3
import { InjectionToken } from '@angular/core';
export type LoggerService = Pick<typeof console,
'debug' | 'error' | 'info' | 'log' | 'trace' | 'warn'>;
export const LOGGER_SERVICE = new InjectionToken('LOGGER_SERVICE');
export const ConsoleLoggerServiceProvider = { provide: LOGGER_SERVICE, useValue: console };
// ...
@NgModule({
providers: [
ConsoleLoggerServiceProvider,
//...
],
// ...
// ...
@Injectable()
export class MyService {
constructor(@Inject(LOGGER_SERVICE) log: LoggerService) {
//...
NPM上现在有一个angular2记录器组件,它支持日志级别。 https://www.npmjs.com/package/angular2-logger
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