javascript indexof object code example

Example 1: javascript indexOf object value in array

// Get index of object with specific value in array
const needle = 3; // needle
const haystack = [{ id: 1 }, { id: 2 }, { id: 3 }]; // haystack
const index = haystack.findIndex(item => item.id === needle);

Example 2: using index of on array of objects

arr = [{x: "a", y: 1}, {x: "something", y: 2}]
arr.findIndex(obj => obj.x === "a" && obj.y === 1);

Example 3: 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 4: indexof javascript

//indexOf - JS method to get 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

//Eg with material ui

<Checkbox
   checked={value.indexOf(option) > -1}
   value={option}
/>

Example 5: 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 6: indexof javascript

Array.indexOf(searchElement, fromIndex)