Need help with JSON and JavaScript.

1.add code to the setContacts method that creates a function named replacer. Code the replacer function so it strips all non-numeric characters from the phone number value. Then, use the replacer function with the stringify method.

"use strict";

var storage = { keyContacts: "contacts_1", getContacts: function() { // get string from local storage var storageString = localStorage.getItem(this.keyContacts) || null; //my code var reviver = function (key, value) { if (key === "") return value; if (key === "p") { switch (value.length) { case "7": return value.subString (0,3) + "-" + subString (3); case "10": return value.subString (0,3) + "-" + subString (3,3) + "-" + subString (6); case "11": return value.subString (0,1) + "-" + subString (1,3) + "-" + subString (4,3) + "-" + subString (7); default: return value; } else { return value; } } }; // convert string to JavaScript object and return, or return empty array if string is null return JSON.parse(storageString) || []; }, setContacts: function(value) { // convert JavaScript object to string var storageString = JSON.stringify(value); //my code var replacer = function (key, value) { } // store string in local storage localStorage.setItem(this.keyContacts, storageString); }, clearContacts: function() { localStorage.setItem(this.keyContacts, ""); } };