Priority hints indicate the relative priority of resources to the browser. They can enable optimal loading and improve Core Web Vitals.

From https://web.dev/priority-hints/

example with fetch API:

<script>
  fetch('https://example.com/', {priority: 'low'})
  .then(data => {
    // Trigger a low priority fetch
  });
</script>

how set "priority" to Angular HttpClient?

I have tried to force a priority setting:

import { HttpClient } from '@angular/common/http';
import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `
  <button (click)="makeRequest()">make request</button><br />
  <pre>{{ data | json }}</pre>`,
})
export class AppComponent implements OnInit {
  data: any;

  constructor(private httpClient: HttpClient) {}

  ngOnInit(): void {
    this.makeRequest();
  }

  makeRequest() {
    this.data = null;
    this.httpClient
      .get('https://jsonplaceholder.typicode.com/todos/1', {
        priority: 'low',
      } as any)
      .subscribe((result) => (this.data = result));
  }
}

online

but doesn't works... priority is always hight

also suggested to angular team https://github.com/angular/angular/issues/45426