JAVASCRIPT

javascript findindex

const array1 = [5, 12, 8, 130, 44];
const search = element => element > 13;
console.log(array1.findIndex(search));
// expected output: 3

const array2 = [
  { id: 1, dev: false },
  { id: 2, dev: false },
  { id: 3, dev: true }
];
const search = obj => obj.dev === true;
console.log(array2.findIndex(search));
// expected output: 2

findindex js

// 	findIndex(callback fn)  

//	.... return index (when condition meets)
//  .... return -1 (if condition not meets)

const array = [5, 12, 8, 130, 44];

/// it returns the index of number which satisfy the condition true
const index = array.findIndex((item)=> item>10);   //1

/// now we can check what element at that index...
console.log(array[index]); // array[1]

javascript array findindex

// find index of array item; test values using a function
const arr = ['A','B','C'];
const index = arr.findIndex((item) => item === 'B');	// index == 1

js FindIndex

const array1 = [5, 12, 50, 130, 44];

const isLarger = (element) => element > 45 ;

const found = array1.findIndex(isLarger);

console.log(found);
//output = 2

javascript findindex

const array1 = [5, 12, 8, 130, 44];
const search = element => element > 13;
console.log(array1.findIndex(search));

const array2 = [
  { id: 1, dev: false },
  { id: 2, dev: false },
  { id: 3, dev: true }
];
const search = obj => obj.dev === true;
console.log(array2.findIndex(search));

findindex method javascript

// .findIndex only accepts a callback function. 
// returns the index of first value for which the function is true

const cities = [
  "Orlando",
  "Dubai",
  "Edinburgh",
  "Chennai",
  "Denver",
  "Eskisehir",
  "Medellin",
  "Yokohama",
  "Denver",
];

const findIndexOfCity = (element) => {
  return element === "Accra" || element === "Yokohama";
};

console.log(cities.findIndex(findIndexOfCity));
// Expected output is 7

//callback functions can take up to 3 arguments. 
//The 1st argument, regardless of what you name it, is always 
//assigned the element being checked. The 2nd argument, optional, 
//is the index of this element. The 3rd argument, also optional, 
//is the entire array.

const findIndexOfLastCity = (element, index) => {
  return element === "Denver" && index > 4;
};

console.log(cities.findIndex(findIndexOfLastCity));
//expected output is 8 (skipped "Denver" at index 4)