var arr=new Array([‘b',2,‘a‘,4]); arr.in_array('b');//判断'b'字符是否存在于 arr 数组中,存在返回true 否则false,此处将返回true 注:此函数只对字符和数字有效 2.遍历 Array.prototype.in_array = function (element) { for ( var i = 0; i < this .length; i++) { if ( this ...
In this article, we'll take a look at how to check if an array includes/contains a value or element in JavaScript. Check Array of Primitive Values Includes a Value Array.includes() Function The simplest way to check for a primitive value in an array is to use the includes() 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 found. Let's take a look at the following example: ...
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();
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); ...
This method returns the first occurrence of the element if it is present more than once within the array.Syntaxarray.indexOf(item, start)Example: Using indexOf() methodIn this example, we have checked whether the value exists within the array or not using indexOf() method....
How to Remove an Element from an Array in JavaScript How to Check if Element is Visible after Scrolling How to Add a Class to a Given Element JavaScript Strings Submit Do you find this helpful? YesNo About Us Privacy Policy for W3Docs ...
If you're using an external library, they also have some built-in methods too 👏 Lodash Checks if value is classified as an Array object. constarray=['🍝','🍜','🍲'];constnotArray='not array';_.isArray(array);// true_.isArray(notArray);// false ...
方法一:array.indexOf 判断数组中是否存在某个值,如果存在,则返回数组元素的下标,否则返回-1。 代码语言:javascript 复制 letarr=[1,2,3,4];letindex=arr.indexOf(3);console.log(index); 方法二:array.includes(searcElement[,fromIndex]) 此方法判断数组中是否存在某个值,如果存在返回true,否则返回false ...
Discover how to efficiently check if a value exists in an array using JavaScript. Learn essential techniques for seamless array manipulation.