js object for each

var obj = { first: "John", last: "Doe" };

Object.keys(obj).forEach(function(key) {
    console.log(key, obj[key]);
});

var obj = {
  first: "John",
  last: "Doe"
};

//
//	Visit non-inherited enumerable keys
//
Object.keys(obj).forEach(function(key) {

  console.log(key, obj[key]);

});

Object.entries(obj).forEach(
    ([key, value]) => console.log(key, value)
);

// Loop using forEach
arr.forEach((item, index) => {
    // TODO
})

// Loop using for...of
for (const item of arr) {
    await something()
}

// Clone new array (not changing the old one)
const arr = [1,2,3]
const newArray = arr.map(item => item * 2)
console.log(newArray)

// Filter array by condition
const arr = [1,2,3,1]
const newArray = arr.filter(item => {
    if (item === 1) { return item }
})
console.log(newArray)

// Join array
const arr1 = [1,2,3]
const arr2 = [4,5,6]
const arr3 = [...arr1, ...arr2]
console.log(arr3)

// Get a property of object
const { email, address } = user
console.log(email, address)

// Copy object/array
const obj = { name: 'my name' }
const clone = { ...obj }
console.log(obj === clone)

const object = {a: 1, b: 2, c: 3};

for (const property in object) {
  console.log(`${property}: ${object[property]}`);
}

Object.keys(object).map(function(objectKey, index) {
    var value = object[objectKey];
    console.log(value);
});

const obj = {
  a: 1, 
  b: 2, 
  c: 3
};
    
for (let key in obj) {
  console.log(key + " = " + obj[key]);
}
// Ausgabe:
// "a = 1"
// "b = 2"
// "c = 3"