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 found. Let's take a look at the following example: ...
const found = arr.some(el => el.username === name); if (!found) arr.push({ id, username: name }); return arr; } console.log(add(arr, 'ted')); Source: stackoverflow.com Check if one element exists in an array of objects var memberships = [{ id: 1, type: 'guest' ...
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', '...
constarray=[1,2,3,4,5];constvalue=3;if(array.indexOf(value)!==-1){console.log("数组中存在该值");}else{console.log("数组中不存在该值");} 使用some()方法: some()方法用于检查数组中是否有元素满足某个条件,如果有则返回true,否则返回false。
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();
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); ...
let user = { name: 'John Doe', age: 17, profession: 'Farmer' }; // Check if key exists let hasKey = user.hasOwnProperty('name'); if (hasKey) { console.log('This key exists.'); } else { console.log('This key does not exist.'); } Checking an Array You might begin to...
if not found, return a false value // function return if an element is found in the array, else falsefunctioncheckTrueExistsArray(array) {for(vark=0;k<array.length;k++) {if(array[k]) {returntrue;break;}}returnfalse;}vararrayVariable=[false,false,true,false,true];vararrayVariable1=[fa...
#Array.push() Element if does not exist using Array.find() This is a three-step process: Use theArray.find()method to iterate over the array. On each iteration, check if the specified value exists in the array. If theArray.find()method returnsundefined, push the value into the array....
For the search feature, we check if the return type of the.indexOf(searchText)is greater than-1. If so, then the search result should betrueelsefalse. Let us look at the same example discussed above to check if an element exists in the array. ...