patterntypescriptangularCritical

Define global constants

Submitted by: @import:stackoverflow-api·Mar 10, 2026·

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defineconstantsglobal

Problem

In Angular 1.x you can define constants like this:

angular.module('mainApp.config', [])
    .constant('API_ENDPOINT', 'http://127.0.0.1:6666/api/')

What would be the equivalent in Angular (with TypeScript)?

I just don't want to repeat the API base url over and over again in all my services.

Solution

Below changes works for me on Angular 2 final version:

export class AppSettings {
   public static API_ENDPOINT='http://127.0.0.1:6666/api/';
}

And then in the service:

import {Http} from 'angular2/http';
import {Message} from '../models/message';
import {Injectable} from 'angular2/core';
import {Observable} from 'rxjs/Observable';
import {AppSettings} from '../appSettings';
import 'rxjs/add/operator/map';

@Injectable()
export class MessageService {

    constructor(private http: Http) { }

    getMessages(): Observable {
        return this.http.get(AppSettings.API_ENDPOINT+'/messages')
            .map(response => response.json())
            .map((messages: Object[]) => {
                return messages.map(message => this.parseData(message));
            });
    }

    private parseData(data): Message {
        return new Message(data);
    }
}

Code Snippets

export class AppSettings {
   public static API_ENDPOINT='http://127.0.0.1:6666/api/';
}

import {Http} from 'angular2/http';
import {Message} from '../models/message';
import {Injectable} from 'angular2/core';
import {Observable} from 'rxjs/Observable';
import {AppSettings} from '../appSettings';
import 'rxjs/add/operator/map';

@Injectable()
export class MessageService {

    constructor(private http: Http) { }

    getMessages(): Observable<Message[]> {
        return this.http.get(AppSettings.API_ENDPOINT+'/messages')
            .map(response => response.json())
            .map((messages: Object[]) => {
                return messages.map(message => this.parseData(message));
            });
    }

    private parseData(data): Message {
        return new Message(data);
    }
}

Context

Stack Overflow Q#34986922, score: 317

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