javascript foreach object

const students = {
  adam: {age: 20},
  kevin: {age: 22},
};

Object.entries(students).forEach(student => {
  // key: student[0]
  // value: student[1]
  console.log(`Student: ${student[0]} is ${student[1].age} years old`);
});
/* Output:
Student: adam is 20 years old
Student: kevin is 22 years old
*/

const object1 = {
  a: 'somestring',
  b: 42
};
for (let [key, value] of Object.entries(object1)) {
  console.log(`${key}: ${value}`);
}
// expected output:
// "a: somestring"
// "b: 42"
// order is not guaranteed

const obj = {
  name: 'Jean-Luc Picard',
  rank: 'Captain'
};

// Prints "name Jean-Luc Picard" followed by "rank Captain"
Object.entries(obj).forEach(entry => {
  const [key, value] = entry;
  console.log(key, value);
});

const list = {
  key: "value",
  name: "lauren",
  email: "[email protected]",
  age: 30
};

// Object.keys returns an array of the keys
// for the object passed in as an argument.

Object.keys(list).forEach(val => {
  let key = val;
  let value = list[val];
  console.log(`${key} : ${value}`);
});

// Returns:
// "key : value"
// "name : lauren";
// "email : [email protected]"
// "age : 30"

const obj = {
  a: "aa",
  b: "bb",
  c: "cc",
};
//This for loop will loop through all keys in the object.
// You can get the value by calling the key on the object with "[]"
for(let key in obj) {
  console.log(key);
  console.log(obj[key]);
}

//This will return the following:
// a
// aa
// b
// bb
// c
// cc

Add thisvar p = {
    "p1": "value1",
    "p2": "value2",
    "p3": "value3"
};

for (var key in p) {
    if (p.hasOwnProperty(key)) {
        console.log(key + " -> " + p[key]);
    }
}

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]);
    }
}

function logArrayElements(element, index, array) {
  console.log('a[' + index + '] = ' + element)
}

// Notice that index 2 is skipped, since there is no item at
// that position in the array...
[2, 5, , 9].forEach(logArrayElements)
// logs:
// a[0] = 2
// a[1] = 5
// a[3] = 9