Set containing a nested collection of maps

Question

Set containing a nested collection of maps

Recently delving into the world of JavaScript and trying to grasp the concept of maps.

This is the code snippet I'm currently working with:

const topmap = new Map();

const map1 = new Map();
const map2 = new Map();

const set1 = new Set();

map1.set('x','y');
map1.set('a','b');

set1.add(map1);
set1.add(map2);
topmap.set('ID',set1);


console.log(topmap.get('ID').size);
topmap.get('ID').forEach(x => {
  if(x.has('x')){x.delete('x')} )
  
  }
)
console.log(topmap.get('ID').size)

Can someone help explain why both lines are returning a size of 2 even after deleting one map in line 18?

javascript set

Answer 1

Answer №1

When dealing with the code snippet topmap.get('ID').size, it is important to note that this represents two map elements within your set1. In order to make changes, be sure you are deleting individual elements from the map rather than the entire map itself.

Answer 2

When dealing with the code snippet topmap.get('ID').size, it is important to note that this represents two map elements within your set1. In order to make changes, be sure you are deleting individual elements from the map rather than the entire map itself.

Answer 3

Answer №2

There is a minor issue in your code snippet above where you have an extra ) at the end of the line if(x.has('x')){x.delete('x')} ).

To remove the entire Map (map1) from the Set (set1), you can simply use the set1.delete(map1) method. Here's the corrected version of the code:

const topmap = new Map();

const map1 = new Map();
const map2 = new Map();

const set1 = new Set();

map1.set('x', 'y');
map1.set('a', 'b');

set1.add(map1);
set1.add(map2);
topmap.set('ID', set1);

console.log(topmap.get('ID').size);

// Delete the Map from the Set
topmap.get('ID').forEach(x => {
  if (x.has('x')) {
    set1.delete(x);
  }
});

console.log(topmap.get('ID').size);  // It should now log 1

Answer 4

There is a minor issue in your code snippet above where you have an extra ) at the end of the line if(x.has('x')){x.delete('x')} ).

To remove the entire Map (map1) from the Set (set1), you can simply use the set1.delete(map1) method. Here's the corrected version of the code:

const topmap = new Map();

const map1 = new Map();
const map2 = new Map();

const set1 = new Set();

map1.set('x', 'y');
map1.set('a', 'b');

set1.add(map1);
set1.add(map2);
topmap.set('ID', set1);

console.log(topmap.get('ID').size);

// Delete the Map from the Set
topmap.get('ID').forEach(x => {
  if (x.has('x')) {
    set1.delete(x);
  }
});

console.log(topmap.get('ID').size);  // It should now log 1

Set containing a nested collection of maps

Answer №1

Answer №2

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