I have a tiny demo and it attempts to read app/data.json using the Angular HttpClient.
const post$:Observable =
Stackblitz currently doesn't serve static files except the case when they are in assets folder.
So you have two options here:
1) Import json directly as module
import data from './data.json';
console.log(data) // => {title: "Simulating HTTP Requsts", content: "This is off the hook!!"}
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2) Move that json in assets folder(Note: you have to reload stackblitz to make it working):
http.get('/assets/data.json')
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