JavaScript Tips for Array Looping and Iteration for Beginners
JavaScript array’s are great ways of storing current state and long list of data. Looping through array is a common task we perform as a developer. Looping is a process through iterate one value upcomming next value. We can also use conditional statement inside loops to determine our output.
JavaScript provides us with statement and methods to loop through array’s so that we can improve this process in effective way. In this post we’ll provide you with so important tips for array looping.
Table of Contents
- Using For Loop
- Using while Loop
- Using do while Loop
- Using For in Loop
- Using For of Loop
- Using forEach() method
- Conclusion
Using For Loop
The for
loop is considered as the simplest among loops because of its structure and inline initialization, condition checking and increamentation of variable.
This loop is easy to debug as all the essential information is declared in single line.
Let us look at a basic example of for
loop.
let names = ["Mathew", "Peter", "Naresh", "Suman", "Rahul"]; console.log("Index | Names"); for(let i = 0; i < names.length; i++){ console.log(i+" "+names[i]); } //Console Output Index | Names 0 Mathew 1 Peter 2 Naresh 3 Suman 4 Rahul

Use of for loop to iterate over names
The .length
is array property which returns number of items in array. The variable i
calls next index items every time its value is incremented.
Using while Loop
In while loop we first declare the index then check condition and at end increment the index value.
top_brands = ["Apple", "Microsoft", "Google", "Reliance", "Mahindra"]; index=0; console.log("Index | Brands"); while(index < top_brands.length){ console.log(index+" "+top_brands[index]); index++; } //Console Output Index | Brands 0 Apple 1 Microsoft 2 Google 3 Reliance 4 Mahindra

Use of while loop in Javascript
The while
loop also serves for multiple purposes such as looping till condition is satisfied.
Let us learn by example.
let top_brands = ["Apple", "Microsoft", "Google", "Reliance", "Mahindra"]; index=0; let search = "Google"; let has_search_result_found = false; while(has_search_result_found==false){ if(top_brands[index]==search){ console.log("Yes your search value "+top_brands[index]+" exists"); has_search_result_found=true; } if(index > top_brands[index].length){ console.log("Sorry no search results found "); break; } index++; } //Console Output Yes your search value Google exists
Using do while
Loop
Do-While loop has a slightly different behaviour compared to other loops. It first iterates and than checks for given condition. This means that first loop of do-while always executes not matter what the given condition is.
let number = 10, index=0; do{ console.log(index); index+=1 }while(index<=0); //Console Output 0
let number = 10, index=0; do{ console.log(index); index+=1 }while(index<=3); //Console Output 0 1 2 3
Using For in Loop
JavaScript For in
loop implicitly retrives array key and loops over all items. Condition checking can be done inside loop and break
statement can be called is condition is met.
let programming_langauges = ["Javascript", "Python", "PHP", "Ruby", "Julia"]; for(let index in programming_langauges){ console.log(programming_langauges[index]) } //Console Output Javascript Python PHP Ruby Julia
In above example index
contains key or index of programming_langauges
array. To display value of that particular array index pass index
inside square brackets of array programming_langauges
.
Using For of Loop
The For of
loop provides easy and simple way of iterating over array and array of objects.
let mobile_brands = ["Apple", "Nokia", "Blackberry"]; for(let mobile_brand of mobile_brands){ console.log(mobile_brand); } //Console Output Apple Nokia Blackberry
Get current index in For of
loop.
let mobile_brands = ["Apple", "Nokia", "Blackberry"]; for(let [index,mobile_brand] of mobile_brands.entries()){ console.log(index, mobile_brand); } //Console Output 0 "Apple" 1 "Nokia" 2 "Blackberry"
Using forEach() method
The forEach()
method is another way of iterating over array of items. This method works on array it call function foreach item.
let names = ["Jack", "John", "James"]; names.forEach((name, index)=>{ console.log(name, index); }); //Console Output Jack 0 John 1 James 2
Conclusion
So its time to say bye we have come to end of our post on JavaScript Tips for Array Looping and Iteration for Beginners.If you like our content then please do share it and comment to clarify your doubts.
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