let array1 = ['node.js', 'php', 'c'];
let array2 = ['php', 'node.js', 'c#', 'c++', 'c'];
let arr = array1.concat(array2);
arr = arr.filter(function (item, index) {
return arr.indexOf(item) === index;
});
console.log(arr);
/*
run:
[ 'node.js', 'php', 'c', 'c#', 'c++' ]
*/