javascript find index of string in array code example

Example 1: how to find the index of a value in an array in javascript

var list = ["apple","banana","orange"]

var index_of_apple = list.indexOf("apple") // 0

Example 2: js find index of string in string

// Find the index of a string in a given sentence
function findNemo(sentence) {
	let indexOfFirst = sentence.split(' ').indexOf('Nemo') + 1;
	if(indexOfFirst >= 0){
		return `I found Nemo at ${indexOfFirst}!`;
	}
	return ("I can't find Nemo :(");
}


console.log(findNemo("I am finding Nemo !"));   //"I found Nemo at 4!"
console.log(findNemo("Nemo is me"));            //"I found Nemo at 1!"
console.log(findNemo("I Nemo am"));             //"I found Nemo at 2!"

Example 3: index of value in array

// for dictionary case use findIndex 
var imageList = [
   {value: 100},
   {value: 200},
   {value: 300},
   {value: 400},
   {value: 500}
];
var index = imageList.findIndex(img => img.value === 200);

Example 4: js array get index

var fruits = ["Banana", "Orange", "Apple", "Mango"];
return fruits.indexOf("Apple"); // Returns 2