how to save to local storage using javascript code example

Example 1: copy localstorage javascript

var data = JSON.parse(/*previously copied stringified JSON from clipboard*/);
Object.keys(data).forEach(function (k) {
  localStorage.setItem(k, data[k]);
});

Example 2: set localstorage

function set(){
    var sendJson = JSON.stringify(arrayName);
    localStorage.setItem('key',sendJson)
}