How do I add a new element in a dictionary in JS?

Question

I have this kind of dictionary: INPUT

movies = {
        'big' : {
            actors : ['Elizabeth Perkins', 'Robert Loggia']
        },
        'forrest gump' : {
            actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise']
        },
        'cast away' : {
            actors : ['Helen Hunt', 'Paul Sanchez']
        }
    };

and I want to use this dictionary to get a different one. For example, I have to make a function called "moviesWithActors" that will received two arguments: "movies" and "actor". Actor could be "Tom Hanks", so when you find that he was on the movie, you don't add to the nested array, but if wasn't, you add.

OUTPUT

movies = {
        'big' : {
            actors : ['Elizabeth Perkins', 'Robert Loggia', 'Tom Hanks']
        },
        'forrest gump' : {
            actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise']
        },
        'cast away' : {
            actors : ['Helen Hunt', 'Paul Sanchez', 'Tom Hanks]
        }
    };

I do this:

for (const value of Object.values(newMovies)){
    console.log(value.actors)
    for (const act of value.actors){
        //console.log(act)
        if (act == actor) {
            console.log("Ok, not add")
        }else{
            console.log("Here I have to add");
        }
    }
}

where "newMovies" is a copy of "movies" and "actor = "Tom Hanks" but I can't add to the array in actors: [ ... ]. Any suggestion? Can I use map() ?

inside first for loop if (!value.actors.includes(actor))value.actors.push(actor) ? — cmgchess
– cmgchess, Commented Jun 7, 2022 at 17:53

Nick · Accepted Answer · 2022-06-08 22:52:17Z

2

As per the requirement what I understood is that there is an existing array of movies object and you want to assign a hero in those movies. We have to ignore if the passed hero name is already there for that movie else add that hero under that movie. If my understanding is correct, Here you go :

const movies = {
  'big' : {
    actors : ['Elizabeth Perkins', 'Robert Loggia']
  },
  'forrest gump' : {
    actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise']
  },
  'cast away' : {
    actors : ['Helen Hunt', 'Paul Sanchez']
  }
};

function updateMoviesList(obj, heroName) {
    Object.keys(obj).forEach(key => {
    if (!obj[key].actors.includes(heroName)) {
        obj[key].actors.push(heroName)
    }
  })
  return obj;
}

console.log(updateMoviesList(movies, 'Tom Hanks'));

edited Jun 8, 2022 at 22:52

Nick

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answered Jun 8, 2022 at 15:03

Rohìt Jíndal

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1 Comment

Nick Over a year ago

Assuming that we interpreted OPs requirements correctly, this is the best way to do it.

Andre Dilay · Accepted Answer · 2022-06-08 15:15:33Z

1

You can use Push()

Like this from docs

let sports = ['soccer', 'baseball']
let total = sports.push('football', 'swimming')

console.log(sports)  // ['soccer', 'baseball', 'football', 'swimming']
console.log(total.length)   // 4

To access array inside dictionary you have first to access it

movies['big']['actors'].push('New Actor')

For not be "hard coded", if you do this?

let actor = 'Tom Hanks'
for (const value of Object.values(newMovies)){
    for (const act of value.actors){
        if (value.actors.includes(actor)) { //Here you check if actor contains in array
            console.log("Ok, not add")
        }else{
            console.log("Here I have to add");
            value.actors.push(actor) //if not push to array          
            }
        }
    }

edited Jun 8, 2022 at 15:15

answered Jun 7, 2022 at 17:34

Andre Dilay

521 silver badge10 bronze badges

4 Comments

Ariel Marcelo Pardo Over a year ago

But I have an array as a value of a dictionary...

Andre Dilay Over a year ago

You have to access the array inside, like movies['big']['actors']. then you can use push like this movies['big']['actors'].push('New Actor')

Ariel Marcelo Pardo Over a year ago

but, I don't want to "hard code" so much my file

Andre Dilay Over a year ago

@ArielMarceloPardo see de edit if fits your needs

Ariel Marcelo Pardo · Accepted Answer · 2022-06-10 01:18:34Z

0

I was suggested to use map instead and the class Object...

function actorInMovies(movies, actor) {
    let mappedObject = { ...movies};
    Object.entries(movies).map(movie => {
        const movieName = movie[0];
        const actors = movie[1].actors;
        if (!actors.includes(actor))
          actors.push(actor);
        mappedObject = {
          ...mappedObject,
          [movieName]: { actors }
        };
      });
    return mappedObject
}

function main(){
    const movies = {
        'big' : {
            actors : ['Elizabeth Perkins', 'Robert Loggia']
        },
        'forrest gump' : {
            actors : ['Tom Hanks', 'Robin Wright', 'Gary Sinise']
        },
        'cast away' : {
            actors : ['Helen Hunt', 'Paul Sanchez']
        }
    };
    const actor = 'Tom Hanks';
    console.log(actorInMovies(movies, actor))
}

main();

answered Jun 10, 2022 at 1:18

Ariel Marcelo Pardo

1567 bronze badges

1 Comment

Ethan Over a year ago

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.

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How do I add a new element in a dictionary in JS?

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1 Comment

You can use Push()

For not be "hard coded", if you do this?

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Your Answer

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3 Answers 3

1 Comment

You can use Push()

For not be "hard coded", if you do this?

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