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Muhammad Zubair
Muhammad Zubair

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Handling Errors in JavaScript.

Hey 👋, Guys Welcome.

Today we will be covering that how to handle with errors in JavaScript and display the custom Error details. Don't Worry this article is gonna be short 😀

Let's Dive In ..


While working with the JavaScript , it mostly happens that we probably get and error dues to the mistakes in coding. this mistake may be in our code or may be a Typo.

Sometimes We have to fetch some data from an API and we are working as asynchronously , then we have to face some difficulty if found any error in our code.

For Handling the Errors we can use try and catch block

  1. try block contains the code that is necessary or have to run
  2. catch block contains the code that is used to handle the errors.

Custom Error

In order to define our custom error we can use the throw operator

Example

try{
  let Object={
    Name:"Muhammad Zubair",
    Age:25
  }

  for (let Key in Object)
  {
    console.log(`${Key}: ${Object[Key]}`)
  }
}
catch(Error){
  console.log("No Error Occured , Code in try-block is Fine")
}
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In Above Example code written in try block will be executed and everything will work fine. we will get no any error, that's why code written in catch block will not be executed.

Let create a scenario in which we get an error. see

Example

try{
  let Array=[1,2,3,4,5]

  console.log(Array) // 1 2 3 4 5
  console.log(B)
}
catch(Error){
  console.log(Error)
}
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In Above example you see that Variable Array was defined and initialized , but variable B was undefined. At First we will get the result of console.log(Array) , after this we will get error due to variable B. On Getting error our code written inside catch block will be executed.

throw operator

As i mentioned earlier that with the help of throw operator we will be able to define our custom error.

Example

try {
  let Array = [];

  if (Array.length == 0) throw "Array is Empty"; // Array is Empty
  else {
    Array.map((Element) => {
      if (Element % 2 == 0) throw "Even Number";
      else throw "Odd Number";
    });
  }
} catch (Error) {
  console.log(Error);
}

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Example

try {
  let Element = 20;

  if (Element % 2 == 0) throw "Even Number"; // Even Number
  else throw "Odd Number";
} 
catch (Error) {
  console.log(Error);
}

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This is it for Today's Lesson.Hope you liked my article 💛. I will meet you in the next post with something new to learn.

Happy Coding !! ⚡

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