js object for each code example

Example 1: javascript foreach object

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"

Example 2: javascript loop through object

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

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

Example 3: js loop over object

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

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

Example 4: foreach object js

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

Example 5: javascript loop through object

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)

Example 6: js object for each

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"