ECMAScript 2015 (ES6) in 2015, JavaScript introduced an important new keyword: const. It has become a common practice to declare arrays using const: Example <!DOCTYPE html> <html> <body> <h2>JavaScript const</h2> <p id=”demo”></p> <script> const cars = [“Saab”, “Volvo”, “BMW”]; document.getElementById(“demo”).innerHTML = cars; </script> </body> </html> Result: JavaScript const Saab,Volvo,BMW Cannot be Reassigned An array declared with const cannot be… Read More »
Array iteration methods operate on every array item. JavaScript Array forEach() The forEach() method calls a function (a callback function) once for each array element. Example <!DOCTYPE html> <html> <body> <h2>JavaScript Array.forEach()</h2> <p>Calls a function once for each array element.</p> <p id=”demo”></p> <script> const numbers = [45, 4, 9, 16, 25]; let txt = “”; numbers.forEach(myFunction); document.getElementById(“demo”).innerHTML… Read More »
Sorting an Array The sort() method sorts an array alphabetically: Example <!DOCTYPE html> <html> <body> <h2>JavaScript Array Sort</h2> <p>The sort() method sorts an array alphabetically:</p> <p id=”demo1″></p> <p id=”demo2″></p> <script> const fruits = [“Banana”, “Orange”, “Apple”, “Mango”]; document.getElementById(“demo1”).innerHTML = fruits; fruits.sort(); document.getElementById(“demo2”).innerHTML = fruits; </script> </body> </html> Result: JavaScript Array Sort The sort() method sorts an array… Read More »
Converting Arrays to Strings The JavaScript method toString() converts an array to a string of (comma separated) array values. Example <!DOCTYPE html> <html> <body> <h2>JavaScript Array Methods</h2> <h2>toString()</h2> <p>The toString() method returns an array as a comma separated string:</p> <p id=”demo”></p> <script> const fruits = [“Banana”, “Orange”, “Apple”, “Mango”]; document.getElementById(“demo”).innerHTML = fruits.toString(); </script> </body> </html> Result: JavaScript… Read More »
An array is a special variable, which can hold more than one value: Why Use Arrays? If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this:let car1 = “Saab”;let car2 = “Volvo”;let car3 = “BMW”; However, what if you want to loop through the cars and find… Read More »
Number methods help you work with numbers. Number Methods and Properties Primitive values (like 3.14 or 2014), cannot have properties and methods (because they are not objects). But with JavaScript, methods and properties are also available to primitive values, because JavaScript treats primitive values as objects when executing methods and properties. The toString() Method The toString() method… Read More »
JavaScript has only one type of number. Numbers can be written with or without decimals. Example <!DOCTYPE html> <html> <body> <h2>JavaScript Numbers</h2> <p>Numbers can be written with or without decimals:</p> <p id=”demo”></p> <script> let x = 3.14; let y = 3; document.getElementById(“demo”).innerHTML = x + “<br>” + y; </script> </body> </html> Result: JavaScript Numbers Numbers… Read More »
Synonyms: Template Literals Template Strings String Templates Back-Tics Syntax Back-Tics Syntax Template Literals use back-ticks (“) rather than the quotes (“”) to define a string: Example <!DOCTYPE html> <html> <body> <h2>JavaScript Template Literals</h2> <p>Template literals use back-ticks (“) to define a string:</p> <p id=”demo”></p> <p>Template literals are not supported in Internet Explorer.</p> <script> let text =… Read More »
JavaScript Search Methods String indexOf() String lastIndexOf() String startsWith() String endsWith() JavaScript String indexOf() The indexOf() method returns the index of (the position of) the first occurrence of a specified text in a string: Example <!DOCTYPE html> <html> <body> <h2>JavaScript String Methods</h2> <p>The indexOf() method returns the position of the first occurrence of a specified text:</p> <p id=”demo”></p> <script>… Read More »
String methods help you to work with strings. String Methods and Properties Primitive values, like “John Doe”, cannot have properties or methods (because they are not objects). But with JavaScript, methods and properties are also available to primitive values, because JavaScript treats primitive values as objects when executing methods and properties. JavaScript String Length The length property… Read More »