Angular 6 download file

Line 5: In this line, we are combining the folder directory path with file name. Now, go to component where you want to implement file downloading code. Open html file and then write this below code in html file. This is just simple button with download click event. Now, in this step, we will create a service.

We will add http post request to call web API. And this service will return file stream as a result. So, go to project folder structure and then create a new service and then write this below code in your service. Line 4: Here in this line, we are calling web API with input parameter.

And web API is returning the data in the form of file stream. Now, in this step, we will install file saver service to download file immediately. So, go to terminal and then run this below command to install file saver. Based on these guards we can now create our custom operator. It'll leverage scan , an operator that allows us to accumulate state for successive values coming through an observable. It takes up to two arguments: First, we provide an accumulator function which will compute the next Download state from the previous one and the current HttpEvent.

Second, we'll pass a seed to scan representing the initial Download state. This seed will represent our download being pending without any progress or content:. Our accumulator will use the previously defined guard to update the Download state over time with information from the HTTP events:. When we encounter a HttpProgressEvent , we calculate the progress based on the number of bytes already loaded and the total bytes.

A download is done when we receive a HttpResponse containing the file contents in its body. When receiving any other events than HttpProgressEvent or HttpResponse , we won't alter the download's state and return it as it is. This way, for example, we can keep the information in the progress property while other events that won't allow us to compute the progress can be ignored for now.

Anything unclear? Let's finally define our custom operator that's using scan with our accumulator and seed :. Notice that this download operator accepts an optional parameter saver. Once a HTTP response is received, this function is invoked with the download content from inside the accumulator.

This allows us to pass in a strategy for persisting the download to a file without directly coupling the operator to FileSaver. By keeping FileSaver. The download operator can be tested without somehow mocking the saveAs import see here for corresponding tests. If we apply the same pattern to the service, we'll be able to test it just as easy. So let's do that by creating a custom injection token for saveAs in a file called saver.

Let's use the Progress Bar from Angular Material to show how far along our download is. The component now only has to assign an observable download to this property:. We can then subscribe to this observable through the AsyncPipe in combination with NgIf. While the download is pending we'll display the progress bar in 'buffer' mode you may also use 'query' , otherwise the progress is determinate. The bar's value can then easily be applied from Download.

Pro Tip : If you need to map something to more than two values inside a template or rather a ternary statement won't do it for you: map the observable to the type you need or use a custom pipe instead of calling a component function from the template.

Both methods are pretty easy to write, more declarative and perform better. Here's a StackBlitz showing everything in action. So I need to register it in providers array of NgModule. Run the Angular application angular-file-download by executing command ng serve --open. When you click on link or button for downloading file you will see below page with file save option:.

When you use the code for displaying data on browser inside download function of controller code and click on button or link, then you should see below output:. For server side code you can read the post on Download file using Angular and Spring Boot. Hi, There is no such step other than running the command for installing file-saver package. You can check what goes wrong in the browser conaole. If only more tutorials on Angular were as succinctly and thoughtfully written as this.

Well done!! I need to show save dialog box to user so he can save file any where. Hi, thank you for your helpful post. Do you know how to download files bigger than 2GB and save them directly on the filesystem? It seems that this way the file lands first in the memory of the browser. Your email address will not be published. Roy Tutorials Technical… Theoretical… Practical…. Introduction In this post I am going to show you how to download file from server using Angular framework.