for each in javascript object code example

Example 1: foreach object javascript

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
*/

Example 2: 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 3: js loop through object

const obj = { a: 1, b: 2 };

Object.keys(obj).forEach(key => {
	console.log("key: ", key);
  	console.log("Value: ", obj[key]);
} );

Example 4: 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 5: loop an object in javascript

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

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

Example 6: for in javascript

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

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

// expected output:
// "a: 1"
// "b: 2"
// "c: 3"