js for i in code example

Example 1: javascript for

let str = "";

for (let i = 0; i < 9; i++) {
  str = str + i;
}

console.log(str);
// expected output: "012345678"

Example 2: loop an object in javascript

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

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

Example 3: for in loop javascript

var person = {"name":"taylor","age":31};
for (property in person) {
	console.log(property,person[property]);
}
//name taylor
//age 31

Example 4: for in loop javascript

let array = [1,2,3,4,5,6,7,8,9,10]; 
// our array that we will use the for loop on
for (let i = 0; i < array.length; i++) { 
  // this loop will console log the element at array[i] starting at 0
  // and will continue looping for i < array.length 
  console.log(array[i]);
  // after each loop i will increase by 1
}

// this will console log
// 1
// 2
// 3
// 4
// 5
// 6
// 7
// 8
// 9
// 10

Example 5: 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"