Under standingrelative and abolute path javascript

Can someone please help me with understanding concept of relative and absolute paths. I am really confused how they work in what directory I am ? I have this following code I can't include PostService module.

import { Component } from '@angular/core';
import { PostService } from '../services/post.service';

@Component({
moduleId: module.id,
selector: 'search',
templateUrl: 'search.component.html',
providers:[PostService]
})

export class SearchComponent  { 
    posts: post[];

    constructor(){
                this.posts = [
        {
            id: 1,
            title:"Post heading",
            body: "They want a self-starter. They don't need more handholding than necessary. They want someone whos not a script kiddy, who knows solid software engineering fundamentals. They want someone who will work well with the team, and be proactive in improving the situation, rathe t just playing the victim when things go wrong."
        },
                    {
            id: 2,
            title:"Post heading",
            body: "They want a self-starter. They don't need more handholding than necessary. They want someone whos not a script kiddy, who knows solid software engineering fundamentals. They want someone who will work well with the team, and be proactive in improving the situation, rathe t just playing the victim when things go wrong."
        },
                    {
            id: 3,
            title:"Post heading",
            body: "They want a self-starter. They don't need more handholding than necessary. They want someone whos not a script kiddy, who knows solid software engineering fundamentals. They want someone who will work well with the team, and be proactive in improving the situation, rathe t just playing the victim when things go wrong."
        }
    ]
    }
}

File structure is as follows:

 -- app
   '-- components
       '-- search
           '-- search.component
    '-- services
        '-- post.service