Transform an array of Boolean values into a string array containing only the values that are true

Question

Transform an array of Boolean values into a string array containing only the values that are true

Suppose we have an object like the following:

likedFoods:{
  pizza:true,
  pasta:false,
  steak:true,
  salad:false
}

We want to filter out the false values and convert it into a string array as shown below:

compiledLikedFoods = ["pizza", "steak"]

Is there a more efficient way to achieve this without using multiple if statements like this:

if (this.likedFoods.pizza == true) {this.compiledLikedFoods.push('pizza')};
if (this.likedFoods.pasta == true) {this.compiledLikedFoods.push('pasta')}'
if (this.likedFoods.steak == true) {this.compiledLikedFoods.push('steak')}'
if (this.likedFoods.salad == true) {this.compiledLikedFoods.push('salad')}'

If so, what would be the best approach?

Thank you.

javascript typescript

Answer 1

Answer №1

I prefer to extract object keys based on their corresponding values

const favoriteFoods = {
  pizza:true,
  pasta:false,
  steak:true,
  salad:false
};
const selectedFood = Object.keys(favoriteFoods).filter(key => favoriteFoods[key] === true);
console.log(selectedFood); //["pizza", "steak"]

Answer 2

I prefer to extract object keys based on their corresponding values

const favoriteFoods = {
  pizza:true,
  pasta:false,
  steak:true,
  salad:false
};
const selectedFood = Object.keys(favoriteFoods).filter(key => favoriteFoods[key] === true);
console.log(selectedFood); //["pizza", "steak"]

Answer 3

Answer №2

If I were to tackle this task, I might opt for either using a loop or leveraging the reduce function on the array obtained from Object.entries:

Utilizing a Loop:

const compiledLikedFoods = [];
for (const [name, value] of Object.entries(likedFoods)) {
    if (value) {
        compiledLikedFoods.push(name);
    }
}

Implementing reduce (as any array operation can be molded into a reduce):

const compiledLikedFoods = Object.values(likedFoods).reduce((array, [name, value]) => {
    if (value) {
        array.push(name);
    }
    return array;
}, []);

However, you may want to check out Andrey's more straightforward solution. (I'm feeling a bit embarrassed now.)

Answer 4

If I were to tackle this task, I might opt for either using a loop or leveraging the reduce function on the array obtained from Object.entries:

Utilizing a Loop:

const compiledLikedFoods = [];
for (const [name, value] of Object.entries(likedFoods)) {
    if (value) {
        compiledLikedFoods.push(name);
    }
}

Implementing reduce (as any array operation can be molded into a reduce):

const compiledLikedFoods = Object.values(likedFoods).reduce((array, [name, value]) => {
    if (value) {
        array.push(name);
    }
    return array;
}, []);

However, you may want to check out Andrey's more straightforward solution. (I'm feeling a bit embarrassed now.)

Answer 5

Answer №3

If you want to filter by value, simply retrieve the keys and then apply the filtering logic.

var favoriteMovies = { action: true, comedy: false, drama: true, horror: false },
    compiledFavoriteMovies = Object.keys(favoriteMovies).filter(k => favoriteMovies[k]);

console.log(compiledFavoriteMovies);

Answer 6

If you want to filter by value, simply retrieve the keys and then apply the filtering logic.

var favoriteMovies = { action: true, comedy: false, drama: true, horror: false },
    compiledFavoriteMovies = Object.keys(favoriteMovies).filter(k => favoriteMovies[k]);

console.log(compiledFavoriteMovies);

Answer 7

Answer №4

If you need to iterate through an object and add keys to an array based on their corresponding true values, you can utilize the for...in loop:

var likedFoods={
  pizza:true,
  pasta:false,
  steak:true,
  salad:false
}
var compiledLikedFoods = [];
for(var o in likedFoods){
  if(likedFoods[o])
    compiledLikedFoods.push(o);
}
console.log(compiledLikedFoods)

Answer 8

If you need to iterate through an object and add keys to an array based on their corresponding true values, you can utilize the for...in loop:

var likedFoods={
  pizza:true,
  pasta:false,
  steak:true,
  salad:false
}
var compiledLikedFoods = [];
for(var o in likedFoods){
  if(likedFoods[o])
    compiledLikedFoods.push(o);
}
console.log(compiledLikedFoods)

Transform an array of Boolean values into a string array containing only the values that are true

Answer №1

Answer №2

Answer №3

Answer №4

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