JSFiddle - React, Tailwind, and code Playground

JavaScript

let size = 9;
let printAll = true;
let f32 = new Float32Array(size).fill(0.3); // input array

// code

let f32json = JSON.stringify(f32);
let f32jsonArr = JSON.stringify(Array.from(f32));
let f32base64 = btoa(String.fromCharCode(...(new Uint8Array(f32.buffer))));

// decode

let df32json = new Float32Array(Object.values(JSON.parse(f32json))); // Object.values return values sorted by numeric keys (look https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/values#Examples)
let df32jsonArr = new Float32Array(JSON.parse(f32jsonArr));
let df32base64 = new Float32Array(new Uint8Array([...atob(f32base64)].map(c => c.charCodeAt(0))).buffer);

// print

console.clear();
if(printAll){
  console.log('Input Array - f32:', f32);
  console.log('Code and decode results:');
  console.log('---------------');
  console.log('f32json:', f32json);
  console.log('df32json:', df32json);
  console.log('---------------');
  console.log('f32jsonArr:', f32jsonArr);
  console.log('df32jsonArr:', df32jsonArr);
  console.log('---------------');
  console.log('f32base64:', f32base64);
  console.log('df32base64:', df32base64);
  console.log('---------------');
}
console.log('Results size (in bytes):',{
  'f32: ': 4*f32.length,  // 4* because 32bit=4bytes
  'f32json': f32json.length, 
  'f32jsonArr': f32jsonArr.length,
  'f32base64': f32base64.length
});