What Is jQuery Migrate?

What Is jQuery Migrate?

jQuery as we already know is an in-built library containing JavaScript functions. It is a JavaScript file that you link to your HTML file. It is used to simplify a lot of complicated things from your JavaScript file.

jQuery is such a huge library that it may require a lot of work to upgrade it. This is where jQuery migrate comes into the picture. It is used to reduce the efforts to upgrade different jQuery versions and makes the task easier and quicker.

What Does jQuery Migrate Do?

It is very difficult to upgrade jQuery especially when many new features have been added. When you introduce new features on top of older ones your code becomes messy. To avoid this jQuery migrate is the best solution.

jQuery migrate adds back the APIs that have been eliminated, and additionally shows errors or feedbacks in the browser (development version of jQuery Migrate only) when the user uses APIs that have been eliminated. Thus making it easier to upgrade jQuery without affecting our code.

jQuery migrate lets your code be compatible especially if it has been written with any versions older than 1.9.

How To Use The jQuery Migrate Plugin?

It is very easy
to use migrate plugin in your HTML code.

In your web page, load the migrate plugin in the <script> tag after the <script> tag for jQuery.

<script src="https://code.jquery.com/jquery-3.4.1.js"></script>
<script src="https://code.jquery.com/jquery-migrate-3.4.2.js"></script>

Example: A simple code to implement jQuery migrate in your HTML file.

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">
<script src="https://code.jquery.com/jquery-migrate-3.5.1.js"></script>
</script>
<script>
$(document).ready(function(){
 
$("button").click(function(){
   
$("p").css({"color": "red"});
  });
});
</script>
</head>
<body>
<h2>
<p>Example To Implement jQuery Migrate</p>
<h2>
<button>Set Text Color To Red</button>
 
</body>
</html>

What Is jQuery Migrate?

What Are The Types Of Migrate Plugin APIs?

Migrate plugin APIs are used to add some properties to the jQuery object. It is used to programmatically control and examine the behavior of jQuery object. There are six jQuery migrate plugin APIs:

1.jQuery.migrateWarnings

With the help of this property, you can print multiple warning messages that have been triggered on the page by your code. The order remains the same as printing the messages like that of the generation of messages. The messages will be printed only one time in the series even if the condition has been triggered more than once. 

Example:

if ( jQuery.migrateWarnings ) {
                       window.console.log( "Migrate plugin loaded multiple times" );
           }

This will print warning
messages at the console.

2.jQuery.migrateMute

When you set jQuery.migrateMute to “true” it mutes the warning messages. Thus, the warnings will not be generated.

jQuery.migrateMute =
true;

Even if this property is set to true, jQuery.migrateWarnings succeeds it and thus you can inspect the warnings without generating them.

3.jQuery.migrateTrace

Sometimes, you may want the messages to be shown on the console of the browser but you would not want stack traces to be shown. You can do this by setting jQuery.migrateTrace to false.

Example:

if (
jQuery.migrateTrace === undefined ) {

     
     jQuery.migrateTrace = true;

}

4.jQuery.migrateReset()

As the name says, jQuery.migrateReset() resets the array. This property is used to clear the jQuery.migrateWarnings array.

Example:

jQuery.migrateReset =
function() {

     
     warnedAbout = {};

     
     jQuery.migrateWarnings.length = 0;

};

5.jQuery.migrateVersion

This property is used to show the version of Migrate that is currently being used.

Example:

window.console.log(
"Migrate installed" + ", version " + jQuery.migrateVersion
);

This will print the
current installed version of migrate.

6.jQuery.migrateDuplicateWarnings

As discussed above, migrate only generates a warning message once even if the condition is triggered many times. You can set jQuery.migrateDeduplicateWarnings to false to get warning messages every time a condition is triggered. But this can be inefficient especially if a loop of warning is triggered.

jQuery.migrateDeduplicateWarnings
= false;

Conclusion

In this tutorial, we learned what is jQuery and how it can be useful to upgrade jQuery to different versions. We also saw the types of migrate APIs, their syntax, and how they can be used. jQuery migrate is one of the APIs that truly make jQuery helpful to web developers.

To learn more such jQuery APIs, subscribe to our blog! If you want to know about jQuery effects, visit our previous article!