javascript case exist in array code example

Example 1: array contains case insensitive javascript

var array = ['I', 'hAve', 'theSe', 'ITEMs'],
    query = 'these',
    result = array.findIndex(item => query.toLowerCase() === item.toLowerCase());

console.log(result); // 2

Example 2: array includes

let storyWords = ['extremely', 'literally', 'actually', 'hi', 'bye', 'okay']
let unnecessaryWords = ['extremely', 'literally', 'actually' ];

let betterWords = storyWords.filter(function(word) {
  return !unnecessaryWords.includes(word);
});
console.log(betterWords) // ['hi' 'bye' 'okay]