Check Element Existence in Arrays (2)

If you work with a hard code values is easy to work with them because you know where are the values inside the array.

example

// you have an array with names
const names = ['name1','name2','name3',...]


// you can access for example name2 because you know the position
console.log(names.indexOf('name2')) // return 1


// but what happen with an item that doesn't exist?
console.log(names.indexOf('name4')) // return -1 that means that the element doesn't exist


// so you can do something like that to check is an item exist

console.log(names.indexOf('name3') === -1 && true); //return true

fortunately for us there is other much easiest way to do this "includes method"

// you have an array with names
const names = ['name1','name2','name3',...]


// use includes method

console.log(names.includes('name4')) // return false

but what happen with more complex data? (objects)

for the more complex data you cannot use includes and those cases you can use 'some' method.

some method

The some method takes a callback function with its own parameters and iterate over each element of the array.

example

// array of objects
const persons = [
  { name: 'random1', age: 5 },
  { name: 'random2', age: 4 },
  { name: 'random3', age: 56 },
  { name: 'random4', age: 11 },
  { name: 'random5', age: 90 },
];


// use some method

persons.some((element) => element.age === 90); // return true or false

with some method at least one element need to match with the condition, once have a match the iteration stop and returns true or false

Hope that you enjoy this post with love Bernardo Aguayo <3