JavaScript Array Methods

1. forEach

• Description: The forEach method executes a provided function once for each array element. It is typically used for side effects, such as logging values or modifying external states.
• Key Use Case: Performing an action on each element in an array without returning a new array.
• Example Use Cases:
  • Logging each element in an array.
  • Modifying elements of the array outside the array scope.

2. map

• Description: The map method creates a new array populated with the results of calling a provided function on every element in the array. It is commonly used for transforming data.
• Key Use Case: Transforming each element in an array to create a new array with modified values.
• Example Use Cases:
  • Creating an array of transformed values from another array.
  • Mapping an array of objects to extract a specific property.

3. filter

• Description: The filter method creates a new array containing all the elements that pass a test provided by a function. It is useful for filtering data based on certain conditions.
• Key Use Case: Extracting elements from an array that meet specific criteria, leaving out those that don't.
• Example Use Cases:
  • Filtering out specific items from an array based on a condition.
  • Creating a list of users above a certain age.

4. reduce

• Description: The reduce method executes a reducer function on each element of the array, resulting in a single output value. It is typically used for accumulating or combining data.
• Key Use Case: Reducing an array to a single value, such as summing values or finding an average.
• Example Use Cases:
  • Summing all elements in an array.
  • Calculating a combined result such as a product or a total from a list.

Summary of Use Cases:

• forEach: Ideal for executing side effects (logging, updating UI) on each array element without returning a new array.
• map: Perfect for transforming or modifying each array element and returning a new array with the results.
• filter: Best suited for creating a new array based on a condition, filtering out unwanted elements.
• reduce: Useful for aggregating array data into a single value, such as calculating totals, averages, or combined results.