hi! jsreport generates reports on the server side but it exposes an http api in order for other clients to invoke report rendering. so in order to integrate jsreport with your Angular front-end or a backend client you just need to start a http request to jsreport http api..
the best way to get the data from your APIs will depend on your preferences, you have some options:
from your Angular front-end start an ajax request to get data from your own API, then with that data call jsreport http api to render your report with that data, we have a browser sdk that handles the sending and showing the report in the browser. you will probably find it useful if you don't want to create the request by yourself.
in your jsreport template configure a script, more specifically a beforeRender script. In the script you can use node.js to start a request to your APIs and then use that data to fill the data that your template needs. so, in other words, you are configuring that jsreport should pull data from your own API before starting to render your report. you can see an example of that here if you scroll down a little bit.
hope that this helps, if you have other questions feel free to ask. we also suggest you to give a full tour of our docs in order to have more context about the features of jsreport.