Pipe vs Directive in Angular

Angular was designed by Google to address challenges programmers face building complex, single-page applications. This JavaScript framework takes care of the back end so you can take care of the client side.

In Angular, pipes, a way to write display-value transformations that you can declare in your HTML. And directives provide functionality and can transform the DOM. The default pipe uses Angular’s ability to pass multiple values into the pipe to get both the value and the default value. A directive is a decorator with no view.

Let's explore the difference between Pipe and Directive in Angular.

Pipe vs Directive

• A user creates/uses a directive that parses the input into a formatted currency string. On the other hand, a pipe can be used in the controller/component triggered by input to filter the value.

• Pipes are for formatting data, and directives are to alter the behavior/appearance of an element.

• A pipe is to manipulate data, while a directive is more for DOM manipulation.

• A pipe gets data as an input, transforms it and outputs this data in another way.

• A directive gets a DOM element it's "attached" to and enhances it with some kind of features.

• A pipe takes in data, as a stringer in a ray and runs some logic to transform it into new output.

• Directives are two types. Structural directives modify layout by altering elements in the DOM. And attribute directives change the behavior or appearance of an existing DOM element.

• Angular comes with some common pipes, like date and upper case and lower case. You can also write your own pipes to handle custom scenarios that fit your application needs.

• Directives do not have a template. There's something you can create with the intent of applying them to an existing element.

• PIpes are a great way to change data in a reusable way that without having to embed the transform logic within component classes and without having to modify the data just for display purposes.

• A directive gets configured with a selector that Angular will use to find a match and apply the directive.

• As in AngularJS, pipes can be stateless (pure functions, not reevaluated) or stateful (has dependencies that can modify the output).

• You can apply a directive in different ways. You can write an attribute on an element that matches your selector, or you can use the template syntax to add a directive in an assignment statement.

• When use pipe, transform show first empty string. And when use directive, show the first path to translate the string.

• Using impure pipes can lead to several performance issues.

• Angular comes with a stock of pipes such as DatePipe, UpperCasePipe, LowerCasePipe, CurrencyPipe, and PercentPipe.