How to Initialize a Map With Values in JavaScript

In the record maintenance processes, there can be a requirement to maintain the data having values against a particular attribute. For instance, to solve algorithm and data structure problems like graphs and minimal distance. In such situations, initializing a map with values using JavaScript assists in logically maintaining the records and utilizing the current resources effectively.

This write-up will discuss the approaches to initializing a map with values in JavaScript.

How to Initialize a Map With Values Using JavaScript?

To initialize a map with values in JavaScript, apply the following approaches in combination with the “Map()” constructor:

• “set()” method.
• “Object.entries()” method.
• “Array” approach.

Let’s discuss each of the stated approaches one by one!

Approach 1: Initialize a Map With Values in JavaScript Using set() Method

The “set()” is a map’s method that sets the key values in a map. This method can be utilized to set the map values in a “key-value” pair with the help of the created map object.

Example

Let’s overview the following example:

In the above lines of code:

• Create a new map object with the help of the “new” keyword and the “Map()” constructor, respectively.
• In the next step, apply the map’s “set()” method to initialize the stated values in a “key-value” pair.
• Lastly, display the initialized map values.

Output

In the above output, it can be observed that the map values are set accordingly.

Approach 2: Initialize a Map With Values in JavaScript Using Object.entries() Method

The “Object.entries()” method gives an object array in the form of enumerable [key, value] pairs. This method can be utilized to initialize a map from the created object.

Syntax

In the above syntax:

“ob” refers to the object whose values in the form of “key-value” pairs need to be returned.

Example

Let’s go through the below-stated demo:

Perform the following steps, as given in the above code:

• Create an “object” having the stated properties and their respective values.
• In the next step, likewise, create a new map named “initMap”.
• Also, apply the “Object.entries()” method to return the object values from the created object in the form of “key-value” pairs and add them to the map.
• Finally, display the map created from the object on the console.

Output

Here, it can be seen that the object values are transformed into the map successfully.

Approach 3: Initialize a Map With Values in JavaScript Using Array Approach

This approach can be implemented to create a map from the declared array.

Example

The below-given example explains the stated concept:

In the above code snippet:

• Declare an array of the specified values.
• This array will be contained in the created map object via the “Map()” constructor, as discussed.
• Lastly, display the created map from an array.

Output

The above output signifies that the array is converted into the map.

Conclusion

The “set()” method, the “Object.entries()” method or the “Array” approach can be applied to initialize a map with values in JavaScript. The set() method can be utilized to simply set the values via the created object, whereas the Object.entries() method and the array approach can be implemented to create a map from the object and array, respectively. This tutorial explained how to initialize/create a map with values in JavaScript.