If the value exists, then the function will return the index value of the element, else it will return -1 Syntax put-array-or-string-here.indexOf() Code //code to check if a value exists in an array using javascript indexOf var fruits_arr = ['Apple', 'Mango', 'Grapes', '...
Topic:JavaScript / jQueryPrev|Next Answer: Use theindexOf()Method You can use theindexOf()method to check whether a given value or element exists in an array or not. TheindexOf()method returns the index of the element inside the array if it is found, and returns -1 if it not ...
此方法将路径作为输入并测试用户的权限。...让我们看下面的示例,该示例使用fs.access()检查给定目录是否存在: const fs = require('fs'); // directory to check if exists const...'does not exist' : 'exists'}`); }); 查看本指南,以了解有关在Node.js应用程序中读写文件的更多信息。
Check if one element exists in an array of objects var memberships = [{ id: 1, type: 'guest' }, { id: 2, type: 'member' } ]; var status = memberships.some(function(el) { return (el.type == 'member'); }); console.log(status); Do comment if you have any doubts or...
constarray=[3,8,12,6,10,2];// Find 10 in the given array.functioncheckForN(arr,n){for(leti=0;i<array.length;i++){if(n===array[i]){return`${true}${n}exists at index${i}`;}}return`${false}${n}does not exist in the given array.`;}checkForN(array,10); ...
In JavaScript, you can check if every element of the first array exists in the second array, in the following ways: Using Array.prototype.every();
This checks if 'name' and 'email' properties exist in the person object. The first check returns true as 'name' exists, while 'email' returns false. The property name must be specified as a string. $ node main.js true false Checking array indices...
const checkKey = (obj, keyName) => { let keyExist = Object.keys(obj).some(key => key === keyName); console.log(keyExist); }; checkKey(user, 'name'); // Return true Using some() for an Array let number = [12, 33, 14, 45]; // Check if key exists number.some(value...
In v3.0.0 or newer, .only() can be used multiple times to define a subset of tests to run: describe('Array', function() { describe('#indexOf()', function() { it.only('should return -1 unless present', function() { // this test will be run }); it.only('should return the...
Write a JavaScript function to check whether an 'input' is an array or not. Test Data: console.log(is_array('w3resource')); console.log(is_array([1, 2, 4, 0])); false true Sample Solution: JavaScript Code: // Function to check if the input is an arrayvaris_array=function(input...