[javascript] how to prevent adding duplicate keys to a javascript array

A better alternative is provided in ES6 using Sets. So, instead of declaring Arrays, it is recommended to use Sets if you need to have an array that shouldn't add duplicates.

var array = new Set();
array.add(1);
array.add(2);
array.add(3);

console.log(array);
// Prints: Set(3) {1, 2, 3}

array.add(2); // does not add any new element

console.log(array);
// Still Prints: Set(3) {1, 2, 3}

Examples related to javascript

need to add a class to an element How to make a variable accessible outside a function? Hide Signs that Meteor.js was Used How to create a showdown.js markdown extension Please help me convert this script to a simple image slider Highlight Anchor Links when user manually scrolls? Summing radio input values How to execute an action before close metro app WinJS javascript, for loop defines a dynamic variable name Getting all files in directory with ajax

Examples related to jquery

How to make a variable accessible outside a function? Jquery assiging class to th in a table Please help me convert this script to a simple image slider Highlight Anchor Links when user manually scrolls? Getting all files in directory with ajax Bootstrap 4 multiselect dropdown Cross-Origin Read Blocking (CORB) bootstrap 4 file input doesn't show the file name Jquery AJAX: No 'Access-Control-Allow-Origin' header is present on the requested resource how to remove json object key and value.?

Examples related to arrays

PHP array value passes to next row Use NSInteger as array index How do I show a message in the foreach loop? Objects are not valid as a React child. If you meant to render a collection of children, use an array instead Iterating over arrays in Python 3 Best way to "push" into C# array Sort Array of object by object field in Angular 6 Checking for duplicate strings in JavaScript array what does numpy ndarray shape do? How to round a numpy array?

Examples related to duplicates

Remove duplicates from dataframe, based on two columns A,B, keeping row with max value in another column C Remove duplicates from a dataframe in PySpark How to "select distinct" across multiple data frame columns in pandas? How to find duplicate records in PostgreSQL Drop all duplicate rows across multiple columns in Python Pandas Left Join without duplicate rows from left table Finding duplicate integers in an array and display how many times they occurred How do I use SELECT GROUP BY in DataTable.Select(Expression)? How to delete duplicate rows in SQL Server? Python copy files to a new directory and rename if file name already exists

Examples related to key-value

Iterate through dictionary values? How can I get key's value from dictionary in Swift? How to add a new object (key-value pair) to an array in javascript? How to search if dictionary value contains certain string with Python Python: How to check if keys exists and retrieve value from Dictionary in descending priority How do you create a dictionary in Java? how to prevent adding duplicate keys to a javascript array How to update value of a key in dictionary in c#? How to create dictionary and add key–value pairs dynamically? How to count frequency of characters in a string?