147 docs tagged with "JavaScript"

An argument is the value of the built-in arguments object.

Arguments are the optional values you pass to a function through an invocator. And parameters are the names you assign to the values.

Array destructuring is a unique technique that allows you to neatly extract an array's value into new variables.

An array object is an element used to bundle multiple unnamed values into a single item. A pair of square brackets defines JavaScript's array object.

An array-like object does not have built-in methods like map(), pop(), and forEach(). However, a regular array has those methods.

An array bundles values that a user cannot name, while an object bundles values that a user can name.

An asynchronous function is a function that runs in its own timing—without waiting for another function to finish its execution first.

call(), apply(), and bind() make it possible for you to change the runtime binding of a function's this keyword from one object to another.

A class field is a property defined directly in a class's body—not inside any of the class's methods.

A JavaScript class is an object constructor that the new keyword uses to create a new object instance.

The clear() method deletes all the items in the specified web storage. It accepts no argument.

A closure is a function that retains access to its lexical scope's features even after its execution closes.

The code tidbits on this page are pictorial explanations of various web development concepts. Use them to learn JavaScript, HTML, CSS.

codePointAt() is a string method that converts a string character to a Unicode code point.

concat() populates a new array with the concatenation of its calling array and its arguments.

concat() creates a new string by concatenating its calling string and its arguments.

CSS variables are the custom CSS properties developers define for easy reuse throughout a stylesheet.

JavaScript data types refer to the kind of values you can assign to JavaScript variables. The two main ones are primitives and non-primitive.

Declaration declares the creation of variables and functions. Initialization occurs when you assign an initial value to a variable.

Default function properties are the built-in variables available in every function declaration.

The difference between document, data, and code is that a document holds data. Data is a page's content. And code is a computer's language.

Encapsulation is the privatization of an object's data while providing publicly available methods for users to operate on the private data.

An enumerable property is a property whose enumerable attribute's value is configured to be true.

every() returns true if all its calling array's items pass its function argument's test. Otherwise, it returns false.

exec() executes a search for a regular expression pattern in its string argument.

filter() creates a new array that contains all the calling array's elements that passed the test specified by the method's argument.

find() finds the calling array's element that first passes the test specified by the method's function argument.

findIndex() finds the index of the calling array's element that first passes the test specified by the method's function argument.

Fisher-Yates shuffle is an algorithm for generating random arrangements of an array.

The forEach() method invokes its argument once for each item of an existing array.

fromCodePoint() is a string method that converts one or more Unicode code points to their string representation.

The getItem() method retrieves the value of a web storage item. It accepts one required argument.

Hoisting refers to JavaScript giving higher precedence to the declaration of variables, classes, and functions during a program's execution.

Learn how to code with simplified code snippets.

A comment tells browsers to ignore a piece of code. Developers typically use comments for notes, debugging, and code deactivation.

The main difference between HTML, CSS, and JavaScript is their functions. HTML is an orator, CSS a stylist, while JavaScript is a commander.

includes() checks if its calling array includes the method's first argument.

includes() checks if its calling string includes the method's first argument.

indexOf() searches its calling array for the first occurrence of the method's string argument.

indexOf() searches its calling string for the first occurrence of the method's string argument.

Function invocation executes a function to retrieve its value. But function calling calls for a function without retrieving its value.

A JavaScript function is an executable piece of code used to bundle a block of zero or more statements.

Logic is the analytical action performed by a computer, which often requires the computer to decide if a condition is true or false.

join() creates a new string by using a comma, or a user-defined separator, to join the elements of an array object.

JSON (JavaScript Object Notation) is a text format for interchanging data between clients (web pages) and servers.

The key() method retrieves a web storage item's name. It accepts one required argument.

lastIndexOf() searches its calling array for the last occurrence of the method's argument.

lastIndexOf() searches its calling string for the last occurrence of the method's argument.

The length property returns the number of properties in the specified web storage.

Lexical scope is the definition area of an expression. Therefore, an item's lexical scope is the place in which the item got created.

map() creates a new array that contains the result of invoking map()'s function argument on each item of the calling array.

JavaScript's match() method creates a new array containing all the patterns that match the method's regular expression argument.

matchAll() creates a new iterator object containing all the patterns—including capturing groups—that match the method's regular expression argument.

The Math.ceil() method rounds up its argument to the nearest integer.

The Math.floor() method rounds down its argument to the nearest integer.

The Math.random() method generates random numbers between zero (inclusive) and one (exclusive).

A JavaScript method is a function used as the value of an object's property.

Minimax algorithm is a recursive function that helps a player minimize the maximum possibility of losing a game.

A module bundler is a tool developers use to bundle an app's modules and dependencies into a single browser-compatible JavaScript file.

JavaScript modules are files that allow you to export their code. Therefore, allowing other JavaScript files to use the exported code.

A namespace is a named container used to store objects of any type. It allows you to use the same object multiple times in the same script.

A naming convention is a pattern generally accepted as a suitable format for naming coding entities like variables, functions, and properties.

The new keyword creates an object from a JavaScript constructor function or class. Therefore, the newly created object becomes an instance of the constructor.

A non-primitive data is a JavaScript value that can contain multiple other values. Object is the only non-primitive data that exist in JavaScript.

Number.isInteger() checks if its argument is an integer. If so, it returns true. Otherwise, the method returns false.

The Number() global method converts its argument to a Number type or NaN.

Object destructuring is a unique technique that allows you to neatly extract an object's value into new variables.

An object is an element you can use to bundle up multiple named values into a single item. A pair of braces define JavaScript's properties object.

Object.assign() copies its source objects' enumerable own properties and assigns them to the target object.

The Object.entries() JavaScript method copies an objects' enumerable own key-value pairs into a new array.

Object.hasOwn() returns true if an object has a specified property as its own property. Otherwise, it returns false.

The Object.keys() JavaScript method copies an objects' enumerable own keys into a new array.

The Object.values() JavaScript method copies an objects' enumerable own values into a new array.

The parseInt() global method parses and converts its string argument from its radix state to a decimal integer.

JavaScript's pop() method removes and returns its calling array's last item. It does not accept any argument.

A JavaScript primitive data type is any plain value used to program a webpage. Examples are Number, Boolean, String, Null, and BigInt.

JavaScript's push() method adds its arguments to the end of its calling array and returns the calling array's new length.

This tutorial will use a simple project to show you how React testing works.

References to valuable tech-related resources

Recursion is a method by which a problem gets solved through iteration. This article will use an example to illustrate recursive functions.

Whenever you use reduce() on an array, the method uses its function argument to reduce its calling array's items to a single value.

A regular expression (RegExp) is a JavaScript element used to bundle the patterns you wish to find in a specific string of characters.

The removeItem() method removes a property from the specified web storage. It accepts one required argument.

replace() returns a new version of its calling string after replacing some specified patterns with a given replacement.

The rest operator is a syntax used to encase the rest of specific user-supplied values into a JavaScript array. It works with functions.

reverse() reverses an array so that its first item becomes the last and its last element becomes the first.

JavaScript scope is all about space. It refers to the area where an item (such as a variable) is visible and accessible to other code.

search() searches its calling string for the first occurrence of the method's regular expression argument.

setItem() sets its key and value arguments in the specified local or session storage object.

JavaScript's shift() method removes and returns its calling array's first item. It does not accept any argument.

Side effect occurs in a program whenever you use an external code in your function, which impacts the function's ability to perform its task.

JavaScript's slice() method duplicates a specified part of its calling array into a new array—without altering the original array.

JavaScript's slice() method duplicates a specified part of its calling string into a new string—without altering the original string.

Hardware is the touchable part of a machine. And software is the program written for hardware to store and run.

some() returns true if some of its calling array's items pass its function argument's test. Otherwise, it returns false.

sort() sorts its calling array's items in ascending (or descending) order and returns the sorted array.

JavaScript's splice() method alters its calling array by adding or removing a specific number of items to/from it.

split() returns an array containing the result of splitting a string into substrings.

The spread operator helps to expand iterables into individual elements. It is effective only when used within an array, function, or object.

A state is a specific event managed by a stateful program. In JavaScript, variables are memories, while variables' values are states.

A JavaScript statement is a piece of code used to instruct the computer on an action to execute. There are five typical types of statements.

The super keyword searches a parent class or object literal for a specified static or prototypal property.

A temporal dead zone is the area of a block where a variable is inaccessible until the computer completely initializes it with a value.

Test-driven development is a coding practice where you write the result you want your program to produce before creating the program.

test() tests its string argument for an occurrence of a regular expression.

Learn the differences between text and font.

JavaScript's this keyword refers to the owner object of the keyword's method or the "this" value of an arrow function's lexical context.

Use the toExponential() method to convert a number to its exponential equivalent.

toFixed() specifies the number of digits browsers should show after a number's decimal point.

toLowerCase() returns the lowercase version of its calling string.

toPrecision() formats a number to a precise length of digits and returns the result as a string.

toString() converts a number to a string of a specified radix.

toUpperCase() returns the uppercase version of its calling string.

The JavaScript trim() method trims whitespace from both ends of a string.

The JavaScript trimEnd() method trims whitespace only at the end of a string.

The JavaScript trimStart() method trims whitespace only at the beginning of a string.

The JavaScript typeof operator returns the data type of a specified operand.

JavaScript's unshift() method adds its arguments to the beginning of its calling array and returns the calling array's new length.

A JavaScript variable is a container used to store data. JavaScript variables differ from mathematical or other generic variables.

Web storage is the JavaScript API browsers provide for storing data locally and securely within a user's browser.

This glossary defines web-related words and abbreviations beginning with A.

This glossary defines web-related words and abbreviations beginning with B.

This glossary defines web-related words and abbreviations beginning with C.

This glossary defines web-related words and abbreviations beginning with D.

This glossary defines web-related words and abbreviations beginning with E.

This glossary defines web-related words and abbreviations beginning with F.

This glossary defines web-related words and abbreviations beginning with G.

This glossary defines web-related words and abbreviations beginning with H.

This glossary defines web-related words and abbreviations beginning with I.

This glossary defines web-related words and abbreviations beginning with J.

This glossary defines web-related words and abbreviations beginning with L.

This glossary defines web-related words and abbreviations beginning with M.

This glossary defines web-related words and abbreviations beginning with N.

This glossary defines web-related words and abbreviations beginning with O.

This glossary defines web-related words and abbreviations beginning with P.

This glossary defines web-related words and abbreviations beginning with Q.

This glossary defines web-related words and abbreviations beginning with R.

This glossary defines web-related words and abbreviations beginning with S.

This glossary defines web-related words and abbreviations beginning with T.

This glossary defines web-related words and abbreviations beginning with U.

This glossary defines web-related words and abbreviations beginning with V.

This glossary defines web-related words and abbreviations beginning with W.

This glossary defines web-related words and abbreviations beginning with Y.

This glossary defines web-related words and abbreviations beginning with Z.

A block is a pair of braces used to group multiple statements. Block typically gets used in JavaScript functions and CSS rulesets.

A function body is where you place a sequence of statements you want to execute.

A parameter specifies the name you wish to call your function's argument.