loop for array and only after do something code example

Example 1: loop through javascript array

let colors = ['red', 'green', 'blue'];
for (const color of colors){
    console.log(color);
}

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]);
    }
}