how to loop through a string and array at once js code example

Example 1: iterate through array js

let arbitraryArr = [1, 2, 3];
// below I choose let, but var and const can also be used 
for (let arbitraryElementName of arbitraryArr) {
  console.log(arbitraryElementName);
}

Example 2: iterate through array javascript

for (var key in validation_messages) {
    // skip loop if the property is from prototype
    if (!validation_messages.hasOwnProperty(key)) continue;

    var obj = validation_messages[key];
    for (var prop in obj) {
        // skip loop if the property is from prototype
        if (!obj.hasOwnProperty(prop)) continue;

        // your code
        alert(prop + " = " + obj[prop]);
    }
}