How to create a Dictionary with Key/Value pairs in angular?

Courtesy from Konrad Rudolph answer

Dictionary is the “correct” name of the interface (= the ADT), i.e. an associative container that maps (usually unique) keys to (not necessarily unique) values.

To summarize: a dictionary is an ADT that maps keys to values. There are several possible implementations of this ADT, of which the hash table is one. Hash is a misnomer but in context it’s equivalent to a dictionary that is implemented in terms of a hash table.

---

Solution 1

Straight forward you can use Map type as recommendation

    //Using Map
    let map = new Map<string, string>();

    map.set("PO1", "closed"); 
    map.set("PO2", "pending_approval");
    map.set("PO3", "open");
    map.set("PO4", "Draft");
    map.set("PO5", "Cancelled");
    map.set("PO6", "Rejected");
    map.set("PO7", "Saved");
    
    //get item
    console.log(map.get('PO1'));
    console.log(map.get('PO5'));
    
    //has item
    console.log(map.has('PO1'));
    console.log(map.has('PO5'));
    
    //delete item
    console.log(map.delete('PO1'));
    console.log(map.delete('PO5'));

---

Solution 2

But if you want custom additional methods you can also create a Dictionary implementation in typescript like as shown below

    //Using Dictionary
    let dict = new Dictionary();
   
    dict.set("PO1", "closed"); 
    dict.set("PO2", "pending_approval");
    dict.set("PO3", "open");
    dict.set("PO4", "Draft");
    dict.set("PO5", "Cancelled");
    dict.set("PO6", "Rejected");
    dict.set("PO7", "Saved");
    
    //get item
    console.log(map.get('PO1'));
    console.log(map.get('PO5'));

    //has item
    console.log(map.has('PO1'));
    console.log(map.has('PO5'));

    //delete item
    console.log(map.delete('PO1'));
    console.log(map.delete('PO5'));

dictionary.ts

    export class Dictionary {
      items = {};
      constructor() {
        this.items = {};
      }
      public has(key) {
        return key in this.items;
      }
      public set(key,value) {
        this.items[key] = value;
      }
      public get(key) {
        return this.items[key];
      }
      public delete(key) {
        if( this.has(key) ){
          delete this.items[key]
          return true;
        }
        return false;
      }
    }

Working Demo

A dictionary is a data type that maps from keys to values, and allows you to get the value for a given key in O(1) time.

In Typescript or Javascript, you can use an Object as a dictionary:

const dictionary = {
  'key1': 'value1',
  'key2': 'value2'
};

console.log(dictionary['key1']); // outputs 'value1'

You can also use the Map type:

const map = new Map<string, number>();
map.set('key1', 100);
map.set('key2', 200);

console.log(map.get('key2')); // outputs 200