How to solve when you get Less @keyframe animation error. Follow the following steps:

• Check less version and upgrade it if it is not latest globally by
  sudo npm install less@3.9.0 -g
  

• Check less version by   lessc -v

•  If above command gives an error "/usr/bin/env: ‘node’: No such file or
  
  directory" then run below command

• ln -s /usr/bin/nodejs /usr/bin/node

(Reason why to run this command - if you install from a package manager
your bin may be called nodejs so you just need to symlink it like so "ln
-s /usr/bin/nodejs /usr/bin/node")

Need to use different values depending on the environment you’re in? If you’re building an app that talks to the Stripe API for example, you’ll want to use your test publishable key during development and then your live publishable key in production. It’s easy to do in Angular using the environment.ts file.

Angular CLI projects already use a production environment variable to enable production mode when in the production environment:
main.ts

// ...
if(environment.production) {
enableProdMode();
}
// ...
And you’ll also notice that by default in the /src/environment folder you have an environment file for development and one for production. Let’s say we want to be a different apiurl depending if we’re in development or production mode:
environment.ts

export const environment = { 
  production: true, 
  apiurl: 'https://api.yourdomain1.com/' 
};
And in our component all we have to do in order to access the variable is the following:
import { Component } from '@angular/core'; 
import { environment } from '../environments/environment'; 
@Component({ ... }) 
export class AppComponent { 
  apiurl: string = environment.apiurl; 
}
And it’s as simple as that! Angular takes care of swapping the environment file for the correct one.
Now in development mode the apiurl variable resolves to https://api.yourdomain.com/ and in production, if you run ng build --prod for example, apiurl resolves https://api.yourdomain1.com/.
Detecting Development Mode With isDevMode()
Angular also provides us with an utility function called isDevMode that makes it easy to check if the app in running in dev mode:
import { Component, OnInit, isDevMode } from '@angular/core'; @Component({ ... }) 
export class AppComponent implements OnInit { 
  ngOnInit() { 
    if (isDevMode()) { 
       console.log('👋 Development!'); 
    } else { 
        console.log('💪 Production!'); 
    } 
  } 
}
Adding a Local Environment
It’s easy to add new environments in Angular CLI projects by adding new entries to the environments field in the .angular-cli.json file. Let’s add a staging environment for example:
.angular-cli.json

"environments": { 
  "dev": "environments/environment.ts", 
  "prod": "environments/environment.prod.ts", 
  "local": "environments/environment.local.ts"
 }
And now we can add a staging environment file and suddenly be a 🐻 if we build the project with ng build --env=staging:
environment.staging.ts

export const environment = {
 production: true, 
 apiurl: 'https://api.yourdomain.com' 
};


    

				
			

npm is most commonly used for managing Node.js modules, but it works for the front-end too. Bower is created solely for the front-end and is optimized with that in mind.

The biggest difference is that npm does nested dependency tree (size heavy) while Bower requires a flat dependency tree (puts the burden of dependency resolution on the user).

A nested dependency means that your dependencies can have their own dependencies which can have their own, and so on. This is really great on the server where you don’t have to care much about the space and latency.