marcandrewb/for of | for in Cheatsheet.md

## for of | for in Cheatsheet.md

      
    Raw
  

              for of | for in Cheatsheet.md
            
          
for...in iterates over the enumerable properties of an object
for...of iterates over the property values of objects

let myString = "test";

// logs 0, 1, 2, 3
for (let i in myString) {
  console.log(i);
}

// logs t, e, s, t
for (let i of myString) {
  console.log(i);
}


for...in should not be used if the index order of the items is important because there is no guarantee they will be given in the intended order
If you only want to iterate over an object's own properties, use getOwnPropertyNames() or something similar, instead of for...in.
You can use const as the variable for either loop, as long as you're not trying to change the value of the variable (thus obeying the rules of const)
You can use statements like break or return to terminate either of these loops before they complete