How to use Try Catch JavaScript?

Try Catch JavaScript

Try Catch JavaScript

A try, catch statement signifies a block of statements that tries & specifies some response if an exception is thrown. A try block can be declared with a catch or lastly & nested with a try-block in JavaScript minus JavaScript Engine complaints. Try, catch is mainly utilized statement in numerous programming languages. Mainly, it’s used in handling error-prone code parts. Try catch statement firstly tests code for every possible error which may consist, and if it may occur it implements activities in tackling the errors. The best programming method is to have the hard code in the try, catch blocks.

Try Block

try{} statement is utilized in writing error-code like not dividable by zero, array-index out of bound-exception, etc. The code requires likely error-testing that is kept in a try block. If an error happens, it goes to catch {} statement for taking best actions & handles the error. Else, it will execute the code that’s written in.

Catch Block

It is utilized for writing or catching error output. This block deals with error code through executing some statements set that are written in the block. The block consists of either an in-built handler or a user-defined exemption handler. The statement executes just when an error predisposed to code requires to be held in a try block. Else, catch block will be skipped.

Remember catch {} block executes just after an execution of try {} block. Moreover, a single try block consists of one or extra catch blocks.

Finally Block

This block is utilized for writing important code including kill connection, close connection, etc. This will execute even if we have an error in a try block.

Syntax

try block

Example

try-catch-javascript

How does Try & Catch Block operates in JavaScript?

Try block operates with either a final block or a catch block. If one does not have all then the JavaScript engine throws an error that tries minus a finally or catch block.

The catch statement operates always with a try block. One can have numerous catch-blocks with one try block.

Throw Statement

It’s utilized for throwing client-defined errors. A client can define & throw their custom errors. If throw statement will be executed, then a statement existing after it won’t be executed. The control is passed directly to catch block.

The syntax is

Throw-Statement

Try, catch and throw syntax

Try, catch and throw syntax

Here, the exemption can be a number, string, boolean value, or object.

Example of throw with try and catch

Example of throw with try and catch

With the assistance of a throw statement, the client creates their errors.

Try, catch, and finally statements

Finally, a statement is an elective statement of the block that’s executed after try & catch statements execution. Finally, the block doesn’t hold the exceptions for being thrown. Every exception remains thrown or not, if finally, statement code is present it will certainly execute. It doesn’t care for output.

Syntax

Try, catch, and finally statements

Try, catch, finally an example

Try-catch-finally-an-example

JavaScript classifies errors into 6 groups. They include

  • RangeError

The number out-of-range has happened, for instance, 1.toPrecision(500). toPrecision essentially offers numbers a decimal value, for instance, 1.000, & a number should not have 500 of that.

  • EvalError

This error happens in the eval function.

  • ReferenceError

Utilizing a variable that hasn’t been declared

  • TypeError

If one uses a value that’s outside the range of anticipated kinds: for instance 1.toUpperCase()

  • SyntaxError

Occurs when assessing a code using a syntax error

  • Uniform Resource Identifier Error

URI Error occurs if one uses unlawful characters in the URI feature

Conclusion

One can utilize JavaScript try/catch sections to test out code. Contents of catch statement run if one tries the statement that cannot perform successfully. Finally, statement executes instantly after either catch or try statements. If you’re developing a site that clients will see, having custom-errors is useful. Custom-errors make sure the client doesn’t become confused when anything goes wrong.

 

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Terry White

Terry White is a professional Drupal & WordPress developer, Web developer, Web designer, Software Engineer, and Blogger. He strives for pixel-perfect design, clean robust code, and a user-friendly interface. If you have a project in mind and like his work, feel free to contact him

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