foreach key javascript code example

Example 1: javascript foreach get key and value

myObject ={a:1,b:2,c:3}

//es6
Object.entries(myObject).forEach(([key, value]) => {
  console.log(key , value); // key ,value
});

//es7
Object.keys(myObject).forEach(key => {
    console.log(key , myObject[key]) // key , value
})

Example 2: javascript foreach object key

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

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

Example 3: js foreach key value

Object.keys(obj).forEach(function (key) {
   // do something with obj[key]
});

Example 4: javascript map foreach

const myArray = ['Sam', 'Alice', 'Nick', 'Matt'];

// Appends text to each element of the array
const newArray = myArray.map(name => {
	return 'My name is ' + name; 
});
console.log(newArray); // ['My name is Sam', 'My Name is Alice', ...]

// Appends the index of each element with it's value
const anotherArray = myArray.map((value, index) => index + ": " + value);
console.log(anotherArray); // ['0: Sam', '1: Alice', '2: Nick', ...]

// Starting array is unchanged
console.log(myArray); // ['Sam', 'Alice', 'Nick', 'Matt']