index of substring javascript code example

Example 1: javascript indexof

//indexOf getting index of array element, returns -1 if not found
var colors=["red","green","blue"];
var pos=colors.indexOf("blue");//2

//indexOf getting index of sub string, returns -1 if not found
var str = "We got a poop cleanup on isle 4.";
var strPos = str.indexOf("poop");//9

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 javascript

let monTableau = ['un', 'deux','trois', 'quatre'] ;
console.log(monTableau.indexOf('trois')) ;