Show Abhi Raj Posted on Aug 5 • Updated on Aug 21 here is the code
Enter fullscreen mode Exit fullscreen mode result:
Enter fullscreen mode Exit fullscreen mode Nested object iteration was one of the biggest things I struggled to wrap my head around when it was introduced to me during my first month in Flatiron School. It's not that it is an inherently difficult task or that its this incredibly complex task, I just had the hardest time keeping up with where I was within the iteration. In this explanation I will break it down into small chunks that will hopefully help to better understand where you are at within the iteration. First things first, there are several ways to access object data in JavaScript:
For this example we will be using multiple for...in loops to dive down into our nested objects, however for anyone learning about objects I HIGHLY recommend you look up the mdn on the first two examples listed above. And with that, I'll get right down to the best possible explanation I can give to a newcomer on nested object iteration: Task:Lets say we have a toy company split up into two teams that each have a their own individual production and sales departments:
Enter fullscreen mode Exit fullscreen mode We've been asked to write a function that finds the job title of an employee given their name as a string. First for...in Loop:To do this, we will begin by making our function
Enter fullscreen mode Exit fullscreen mode Here is what our Lets break this for...in loop down a bit. We can see form the LOG statements that our loop iterated through the first level of objects within the "for each key on the
first level of In our case, the code below is simple the Second for...in Loop:So we've successfully made it through the first level, but now how do we get to the next level of objects? That's right! another for...in loop! lets add a nested for...in loop to our function and console.log() the results:
Enter fullscreen mode Exit fullscreen mode Here is what our Let's break it down. We've determined that after our first for...in loop we had successfully reached both The first thing we've done is declared another variable, "whichever team key I am currently on in my first for...in loop iteration, I will assign all object data inside of that key to the variable of If you were to
This means we have now reached the department level of the nested objects (i.e. production, sales). Now that we can reference the department level of objects via the variable
"for each key on the first level of When we Third (and Final) for...in Loop:Now we can dive down into our final loop to reach the last level of nested objects and find Todd. Lets take a look at the code below:
Enter fullscreen mode Exit fullscreen mode Our result: If you understand how the second loop worked, the third is simply a repetition with a slight change of code at the end. lets walk through it. Our second for...in loop has gotten us down to the department level of objects (i.e. production, sales). The third loop will get us to the employees. Again we declare a
variable
Next we have our third for...in loop that basically says: "for each key on the first level of Again, this is nothing different than the second for...in loop. Now that we have access to the job title key via the The if statement is basically saying: "If the employees name attached to the current key I am on( and upon calling Conclusion:I'll conclude this post by saying that I am very aware there are much more code-efficient ways to go about accomplishing this task, however, for learning purposes as a beginner, this method helps understand the basics of how things are working. It proved to be a rather steep learning curve for myself and probably is for others I can imagine. Hope this explanation helps! Happy coding and happy learning! How to use loop for nested object in JavaScript?Because for each nested object, we have to loop over it. It is practically impossible to add for...in loop for every nested object because we might not know how many nested objects we have. const nestedObject = (obj) => { for (const key in obj) { if (isObject(obj[key])) { nestedObject(obj[key]); } else { console.
How to loop through object of objects in JavaScript?Methods to loop through objects using javascript. for...in Loop. The most straightforward way to loop through an object's properties is by using the for...in statement. ... . keys() Method. Before ES6, the only way to loop through an object was through using the for...in loop. ... . values() Method. The Object. ... . entries() Method.. How do you loop through an infinite nested array?“how to loop thru a nested array” Code Answer. let chunked = [[1,2,3], [4,5,6], [7,8,9]]; . for(let i = 0; i < chunked. length; i++) { ... . for(let j = 0; j < chunked[i]. length; j++) { ... . console. log(chunked[i][j]); }. How do I map a nested object?How do I map a nested object in react JS? Use the map() method to iterate over the outer array. On each iteration, call the map() method on the nested array. Render the elements of the nested array.
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