Check out example codes for "how push objects into a local stotage array". It will help you in understanding the concepts better.

Code Example 1

// Get the existing data
var existing = localStorage.getItem('myFavoriteSandwich');

// If no existing data, create an array
// Otherwise, convert the localStorage string to an array
existing = existing ? existing.split(',') : [];

// Add new data to localStorage Array
existing.push('tuna');

// Save back to localStorage
localStorage.setItem('myFavoriteSandwich', existing.toString());

Learn ReactJs, React Native from akashmittal.com