App.svelte

<script>
  import Auth from '@aws-amplify/auth';
  import { onMount } from 'svelte';
  import axios from 'axios';
  Auth.configure(
    {
      Auth: {
        region: 'region',
        userPoolId: 'pool_id',
        userPoolWebClientId: 'client_id'
      }
    }
  );


  async function get_access_token() {
    const { accessToken } = await Auth.currentSession();
    return accessToken.getJwtToken();
  }

  async function signIn() {
    try {
      const user = await Auth.signIn('username', 'password');
      console.log(user);
    } catch (error) {
      console.log('error signing in', error);
    }
  }

  async function list_users() {
    const { data } = await axios.get(
      'url',
      {
        headers: {
          'Authorization': `${await get_access_token()}`
        }
      }
    )
    return data;
  }


  export let name;
  let data = [];

  onMount(async () => {
    await signIn();
    data = await list_users();
  });
</script>

<main>
    <h1>Hello {name}!</h1>
    <div>
        {#each data as result}
            <p>{result.name}</p>
        {/each}
    </div>
</main>

<style>
    main {
        text-align: center;
        padding: 1em;
        max-width: 240px;
        margin: 0 auto;
    }

    h1 {
        color: #ff3e00;
        text-transform: uppercase;
        font-size: 4em;
        font-weight: 100;
    }

    @media (min-width: 640px) {
        main {
            max-width: none;
        }
    }
</style>

rollup.config.js

import svelte from 'rollup-plugin-svelte';
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';
import livereload from 'rollup-plugin-livereload';
import json from "@rollup/plugin-json"; // new!
import { terser } from 'rollup-plugin-terser';

const production = !process.env.ROLLUP_WATCH;

function serve() {
	let server;
	
	function toExit() {
		if (server) server.kill(0);
	}

	return {
		writeBundle() {
			if (server) return;
			server = require('child_process').spawn('npm', ['run', 'start', '--', '--dev'], {
				stdio: ['ignore', 'inherit', 'inherit'],
				shell: true
			});

			process.on('SIGTERM', toExit);
			process.on('exit', toExit);
		}
	};
}

export default {
	input: 'src/main.js',
	output: {
		sourcemap: true,
		format: 'iife',
		name: 'app',
		file: 'public/build/bundle.js'
	},
	plugins: [
		svelte({
			// enable run-time checks when not in production
			dev: !production,
			// we'll extract any component CSS out into
			// a separate file - better for performance
			css: css => {
				css.write('bundle.css');
			}
		}),

		// If you have external dependencies installed from
		// npm, you'll most likely need these plugins. In
		// some cases you'll need additional configuration -
		// consult the documentation for details:
		// https://github.com/rollup/plugins/tree/master/packages/commonjs
		resolve({
			browser: true,
      preferBuiltins: false,
			dedupe: ['svelte']
		}),
		commonjs(),
    json(),

		// In dev mode, call `npm run start` once
		// the bundle has been generated
		!production && serve(),

		// Watch the `public` directory and refresh the
		// browser on changes when not in production
		!production && livereload('public'),

		// If we're building for production (npm run build
		// instead of npm run dev), minify
		production && terser()
	],
	watch: {
		clearScreen: false
	}
};