var objArr1 = [{id: "1", fruit: "apple"},{id: "2", fruit: "banana"}];
var objArr2 = [{id : "3", fruit: 'mango'}, {id: "4", fruit: "pear"}];
Array.prototype.push.apply(ObjArr1,ObjArr2);
console.log(ObjArr1); // final merged result will be in ObjArr1
// ObjArr1 => [{id: "1", fruit: "apple"},{id: "2", fruit: "banana"},{id : "3", fruit: 'mango'}, {id: "4", fruit: "pear"}]