The forEach() method calls a function and iterates over the elements of an array. The forEach() method can also be used on Maps and Sets.
JavaScript forEach
The syntax of the forEach() method is:
array.forEach(function(currentValue, index, arr))
Here,
- function(currentValue, index, arr) - a function to be run for each element of an array
- currentValue - the value of an array
- index (optional) - the index of the current element
arr (optional) - the array of the current elements
forEach with Arrays
The forEach() method is used to iterate over an array. For example,
Output
John Sara Jack
In the above program, the forEach() method takes myFunction() function that displays each element of a students array.
Updating the Array Elements
As we have seen in the above example, the forEach() method is used to iterate over an array, it is quite simple to update the array elements. For example,
Output
["Hello John", "Hello Sara", "Hello Jack"]
forEach with Arrow Function
You can use the arrow function with the forEach() method to write a program. For example,
Output
John Sara Jack
for loop to forEach()
Here is an example of how we can write a program with for loop and with forEach().
Using for loop
Output
["item1", "item2", "item3"]
Using forEach()
for...of with Sets
You can iterate through the Set elements using the forEach() method. For example,
Output
1 2 3
forEach with Maps
You can iterate through the Map elements using the forEach() method. For example,
Output
name- Jack age- 27