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Google Maps


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Sat Nov 07 2020 22:27:26 GMT+0000 (UTC)

Posted by @narro #typescript #googlemaps

import { User } from './User'
import { Company } from './Company'

// Instructions to every other class on how they can be an argument to 'addMarker'
// Interface acts as a gatekeeper for props. Does the prop qualify? If so, it can be an argument to the function
interface Mappable {
  location: {
    lat: number;
    lng: number;
  }
}

export class CustomMap {
  private googleMap: google.maps.Map;
  
  constructor(divId: string) {
    this.googleMap = new google.maps.Map(document.getElementById(divId), {
      zoom: 1,
      center: {
        lat: 0,
        lng: 0
      }
    })
  }

  // TS will compare User and Company types and only allow mutual props to be referenced in this function
  addMarker(mappable: Mappable): void {
    // typing 'mappable.' will use intellisense to show props that can be mapped here
    new google.maps.Marker({
      map: this.googleMap,
      position: {
        lat: mappable.location.lat,
        lng: mappable.location.lng
      }
    })
  }

}


// Company and User will be included below for reference
// Company.ts

import faker from 'faker'

export class Company {
  companyName: string;
  catchPhrase: string;
  location: {
    lat: number;
    lng: number;
  }

  constructor() {
    this.companyName = faker.company.companyName()
    this.catchPhrase = faker.company.catchPhrase()
    this.location = {
      lat: parseFloat(faker.address.latitude()),
      lng: parseFloat(faker.address.longitude())
    }

  }
}



// User.ts
import faker from 'faker'

// 'export' will export specific variables - imports will be done in curly braces
// 'export default' should nearly never be used in TypeScript - importing default exports won't use curly braces

export class User {
  name: string;
  location: {
    lat: number;
    lng: number;
  }

  // Objects aren't defined when the class is created so you can not assign values to keys without instantiating the object first
  constructor() {
    this.name = faker.name.firstName()
    this.location = {
      lat: parseFloat(faker.address.longitude()),
      lng: parseFloat(faker.address.latitude())
    } 
  }
}


// Execution - index files:
// index.ts
import faker from 'faker'

// 'export' will export specific variables - imports will be done in curly braces
// 'export default' should nearly never be used in TypeScript - importing default exports won't use curly braces

export class User {
  name: string;
  location: {
    lat: number;
    lng: number;
  }

  // Objects aren't defined when the class is created so you can not assign values to keys without instantiating the object first
  constructor() {
    this.name = faker.name.firstName()
    this.location = {
      lat: parseFloat(faker.address.longitude()),
      lng: parseFloat(faker.address.latitude())
    } 
  }
}

// index.html
// the 'DOCTYPE' heading will cause Google Maps to fail, not sure why
<!-- <!DOCTYPE html> -->
<html>
  <head charset="utf-8">
    <title>Maps</title>
  </head>
  <body>
    <div id="map" style="height: 100%"></div>
    <script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyBNLrJhOMz6idD05pzfn5lhA-TAw-mAZCU"></script>
    <script src="./src/index.ts"></script>
  </body>
</html>
content_copy Copy

Google Map app for adding markers based on Latitude and Longitude. The faker.js library is included to populate fake user and company data.