near_persistence_map_demo.ts

import { PersistentVector, PersistentMap } from "near-sdk-core";

@nearBindgen
class Organization {
  name: string;
  about: string;
  orgId: string;

  constructor(name: string, about: string, orgId: string) {
    this.name = name;
    this.about = about;
    this.orgId = orgId;
  }
}

@nearBindgen
export class Contract {
  //PersistentVector is required to keep track of the keys.
  keys: PersistentVector<string> = new PersistentVector<string>("keys");
  organizations: PersistentMap<string, Organization> = new PersistentMap<
    string,
    Organization
  >("orgs"); //key:orgCode, value: org object. Value could be of any type.

  @mutateState()
  addOrganization(orgId: string, orgName: string, orgAbout: string): string {
    orgId = orgId.toUpperCase(); //Uppercase organization IDs to ease comparisons.

    let o = new Organization(orgName, orgAbout, orgId);

    this.keys.push(orgId); //save the keys here while saving the value objects
    this.organizations.set(orgId, o);

    return "Organization created with code= " + orgId + " and name= " + orgName;
  }

  getOrganizations(): Map<string, Organization> {
    //maps can't be returned directly. You need to copy the values to a temp normal map and return it
    const res: Map<string, Organization> = new Map<string, Organization>();
    for (let i = 0; i < this.keys.length; i++) {
      res.set(this.keys[i], this.organizations.getSome(this.keys[i]));
    }
    return res;
  }
  
  //if you gonna need delete for any reason, u have to maintain the keys vector deletion as well.
}