TypeScript Tutorials

How to Check if a Map is Empty in TypeScript

How to Check if a Map is Empty in TypeScript ?

Answer

To check if a map is empty in TypeScript, you can use the size property. This property returns the number of elements in the map.

✐ Examples

1 Checking if a Map is Empty Using size Property

We can check if a map is empty in TypeScript using the size property, which returns 0 if the map contains no elements and a positive number otherwise.

For example,

We start by declaring and initializing an empty map named myMap. In this example, the map has string keys and integer values.
We use the size property to check if the map is empty. The size property returns the number of elements in the map.
If the size is zero, we print a message indicating that the map is empty. Otherwise, we print a message indicating that the map is not empty.

TypeScript Program

let myMap: Map<string, number> = new Map();

// Check if the map is empty using size property
const isEmpty = myMap.size === 0;

// Print the result
console.log(`Is the map empty? ${isEmpty ? 'Yes' : 'No'}`);

Output

Is the map empty? Yes

2 Checking if a Non-Empty Map is Empty Using size Property

We can check if a non-empty map is empty in TypeScript using the size property, which returns a positive number if the map contains elements.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the size property to check if the map is empty. The size property returns the number of elements in the map.
If the size is zero, we print a message indicating that the map is empty. Otherwise, we print a message indicating that the map is not empty.

TypeScript Program

let myMap: Map<string, number> = new Map([
    ['one', 1],
    ['two', 2],
    ['three', 3]
]);

// Check if the map is empty using size property
const isEmpty = myMap.size === 0;

// Print the result
console.log(`Is the map empty? ${isEmpty ? 'Yes' : 'No'}`);

Output

Is the map empty? No

3 Checking if a Map is Empty After Clearing Using size Property

We can check if a map is empty in TypeScript after clearing its elements using the size property, which returns 0 if the map contains no elements.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the clear method to remove all elements from the map, making it empty.
We use the size property to check if the map is empty after clearing. The size property returns the number of elements in the map.
If the size is zero, we print a message indicating that the map is empty. Otherwise, we print a message indicating that the map is not empty.

TypeScript Program

let myMap: Map<string, number> = new Map([
    ['one', 1],
    ['two', 2],
    ['three', 3]
]);

// Clear the map
myMap.clear();

// Check if the map is empty using size property
const isEmpty = myMap.size === 0;

// Print the result
console.log(`Is the map empty? ${isEmpty ? 'Yes' : 'No'}`);

Output

Is the map empty? Yes

Summary

In this tutorial, we learned How to Check if a Map is Empty in TypeScript language with well detailed examples.

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How to Check if a Map is Empty in TypeScript