Javascript Table

Michael Zippo 04.11.2021

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The JavaScript include () method searches for an element in an array. This method returns True if the array element exists. The filter () method allows you to search for an item in a list. Unlike include (), the filter () method returns the item you searched for.

You might want to know if this array contains a particular value. For example, you may have a list of product orders and want to check if someone has ordered a nightstand from your store.

JavaScript Array contains

There are two ways to determine if a JavaScript booleans .

Array. include () works the same as String.includes (). But Array.includes () searches for an array of objects.

includes () JavaScript Example

Suppose we are having a cafe. We want to check if anyone has ordered an espresso today. We could use the following code to check today’s order list to see if an order has been placed for an espresso:

Our code returns: false.

The todays_orders array does not include the Express value. So when our include () is executed, returns the value false. If we were to search for an array where the element existed, includes () would return true.

Now let’s talk or whatever we want and if anyone has ordered a cappuccino in the last three orders. We could use the includes () method with an start_position argument to do this.

Here is the code we would use:

Our program returns: true. Since a milk was sorted after the index value 3 in our array, our includes () function returned a value true.

In the example above, we used includes () to check if an array of strings included a particular value. But what if we wanted to check if an array of objects contains a specific value ? We can use the filter () function to perform this action.

The filter () function iterates through an array of objects and searches for a particular value. filter () takes one argument: a function used to search for a value. Here is the syntax of the filter () JavaScript function:

filter () JavaScript example

We have an item table for ordering coffee which contains both the name of the coffee ordered and the name of the customer .

We want to check if someone named John Appleseed ordered a coffee today. John is a loyal customer and should have gotten a discount on his next coffee.

The following code checks if John Appleseed has placed an order:

Our program returns:

First, we declare an array called commands. This stores a list of the names of the people I have ordered with and the drink they ordered. Next, we declare a JavaScript variable called check_orders. This variable uses the filter () function to check if someone named John Appleseed has ordered a coffee today.

Let’s print and transfer the value of the check_orders variable to the JavaScript console . Since John Appleseed placed an order today, our function returns his order record. If you do not place an order, our program will not return anything.

If you want to know more about the filter () method, see our tutorial on the JavaScript filter () and reduce () .

Conclusion

The includes () method checks if a value is in an array. This method returns true or false depending on the result. The filter () method determines whether an array of objects contains a particular value. This method returns the object that matches a given criterion if it exists in the array.

Want to learn more about JavaScript? Check out our How to Learn JavaScript guide. You’ll find expert advice and a list of the best online courses, books, and resources you can use to help you learn.

We hope this article has helped you to resolve the problem. Apart from Javascript Table, check other array Python module-related topics.