Dictionaries.ts

Directionaries.ts

import {assert} from 'chai';

export namespace Dictionaries {
    
    /**
      * Create a deep copy of a dictionary such that all of the origina keys are maintained 
      * and copied into a new dictionary. 
      * 
      * This is used when we have to create a copy of a dictionary to prevent concurrent mutation 
      * or when we need to copy it and then make changes to the new dictionary.
      * 
      * The values in the map could be arrays, other dictionaries, sets, maps, strings, arrays, etc.
      * 
      * Make sure to handle all cases.
      *
      * This needs to be fully recursive including dictionaries contain other dictionaries 
      * and arrays.
      */
    export function deepCopy(dict: {[key: string]: any}) {
        
        // TODO: implement this function from the above function definition.
        const result = {}
        Object.keys(dict).forEach(key => {
            if (dict[key] !== 'object') {
                result[key] = dict[key]
            } else {
                result[key] = deepCopy(dict[key])
            }
        }, {})
        
        return result
    }
}


describe("Dictionaries", function() {
    
    // TODO: make sure all of the following tests pass with your new code. 
    
    it("basic tests", function() {
         
         const dict: any = {
             "hello: "world"    
         };
         
         const copy = Dictionaries.deepCopy(dict);
         
         assert.deepEqual(dict, copy);
         
     });

     it("basic integrity", function() {
         
         const dict: any = {
             "hello: "world"    
         };
         
         const copy = Dictionaries.deepCopy(dict);
         
         dict['foo'] = 'bar';
         
         assert.deepEqual(copy, {
             "hello: "world"    
         });
         
     });

    
    
     it("inner integrity", function() {
         
         const dict: any = {
             "hello: "world",
             "inner": {
                "foo": "bar"
            }
         };
         
         const copy = Dictionaries.deepCopy(dict);
         
         dict['inner']['foo'] = 'cat';
         
         assert.deepEqual(copy, {
             "hello: "world",
             "inner": {
                "foo": "bar"
            }
         });
         
     });

    
});