How many data types in javascript
Programming languages all have built-in data structures, but these often differ from one language to another. This article attempts to list the built-in data structures available in JavaScript and what properties they have. These can be used to build other data structures. Wherever possible, comparisons with other languages are drawn. JavaScript is a dynamic language with dynamic types. Variables in JavaScript are not directly
associated with any particular value type, and any variable can be assigned (and re-assigned) values of all types: JavaScript is also a weakly typed language, which means it allows implicit type conversion when an operation involves mismatched types, instead of throwing type errors.
Implicit coercions is very convenient, but can be a potential footgun if developers didn't intend to do the conversion, or intend to convert in the other direction (for example, string to number instead of number to string). For symbols and BigInts, JavaScript has intentionally disallowed certain implicit type conversions. JavaScript typesThe set of types in the JavaScript language consists of primitive values and objects.
Primitive valuesAll types except objects define immutable values (that is, values which can't be changed). For example, Strings are immutable. We refer to values of these types as "primitive values". Boolean typeBoolean represents a logical entity and can have two values: Null typeThe Null type has exactly
one value: Undefined typeA variable that has not been assigned a value has the value Numeric typesECMAScript has two built-in numeric types: Number and BigInt — along with the related value NaN. Number typeThe Number type is a double-precision 64-bit binary format IEEE 754 value. It is capable of storing positive floating-point numbers between 2^-1074
( Note: You can check if a number is within the range of safe integers using
Values outside the range ±(2^-1074 to 2^1024) are automatically converted:
The Number type has only one integer with multiple representations:
Although a number often represents only its value, JavaScript provides bitwise operators. Note: Although bitwise operators can be used to represent several Boolean values within a single number using bit masking, this is usually considered a bad practice. JavaScript offers other means to represent a set of Booleans (like an array of Booleans, or an object with Boolean values assigned to named properties). Bit masking also tends to make the code more difficult to read, understand, and maintain. It may be necessary to use such techniques in very constrained environments, like when trying to cope with the limitations of local storage, or in extreme cases (such as when each bit over the network counts). This technique should only be considered when it is the last measure that can be taken to optimize size. BigInt typeThe BigInt type is a numeric primitive in JavaScript that can represent integers with arbitrary precision. With BigInts, you can safely store and operate on large integers even beyond the safe integer limit for Numbers. A BigInt is created by appending You
can obtain the largest safe value that can be incremented with Numbers by using the constant This example demonstrates, where
incrementing the
You can use the operators A BigInt behaves like a Number in cases where it is converted to boolean:
NaN
String typeJavaScript's String type is used to represent textual data. It is a set of "elements" of 16-bit unsigned
integer values. Each element in the String occupies a position in the String. The first element is at index JavaScript strings are immutable. This means that once a string is created, it is not possible to modify it. However, it is still possible to create another string based on an operation on the original string. For example:
Beware of "stringly-typing" your code!It can be tempting to use strings to represent complex data. Doing this comes with short-term benefits:
With conventions, it is possible to represent any data structure in a string. This does not make it a good idea. For instance, with a separator, one could emulate a list (while a JavaScript array would be more suitable). Unfortunately, when the separator is used in one of the "list" elements, then, the list is broken. An escape character can be chosen, etc. All of this requires conventions and creates an unnecessary maintenance burden. Use strings for textual data. When representing complex data, parse strings, and use the appropriate abstraction. Symbol typeA Symbol is a unique and immutable primitive value and may be used as the key of an Object property (see below). In some programming languages, Symbols are called "atoms". For more details see the
ObjectsIn computer science, an object is a value in memory which is possibly referenced by an identifier. PropertiesIn JavaScript, objects can be seen as a collection of properties. With the object literal syntax, a limited set of properties are initialized; then properties can be added and removed. Property values can be values of any type, including other objects, which enables building complex data structures. Properties are identified using key values. A key value is either a String value or a Symbol value. There are two types of object properties: The data property and the
accessor property. Each property has corresponding attributes. Each attribute is accessed internally by the JavaScript engine, but you can set them through Data propertyData properties associate a key with a value. It can be described by the following attributes: value The value retrieved by a get access of the property. Can be any JavaScript value. writable A boolean value indicating if the property can be changed with an assignment. enumerable A boolean value indicating if the property can be enumerated by a configurable A boolean value indicating if the property can be deleted, can be changed to an accessor property, and can have its attributes changed. Accessor propertyAssociates a
key with one of two accessor functions ( Note: It's important to recognize it's accessor property — not accessor method. We can give a JavaScript object class-like accessors by using a function as a value — but that doesn't make the object a class. An accessor property has the following attributes: get A function called with an empty argument list to retrieve the
property value whenever a get access to the value is performed. See also getters. May be set A function called with an argument that contains the assigned value. Executed whenever a specified property is attempted to be changed. See also
setters. May be enumerable A boolean value indicating if the property can be enumerated by a configurable A boolean value indicating if the property can be deleted, can be changed to a data property, and can have its attributes changed. "Normal" objects, and functionsA JavaScript object is a mapping between keys and values. Keys are strings (or Symbols), and values can be anything. This makes objects a natural fit for hashmaps. Functions are regular objects with the additional capability of being callable. DatesWhen representing dates, the best choice is to use the built-in
Indexed collections: Arrays and typed ArraysArrays are regular objects for which there is a particular relationship between integer-keyed properties and the Additionally, arrays inherit from Typed Arrays present an array-like view of an underlying binary data buffer, and offer many methods that have similar semantics to the array counterparts. "Typed array" is an umbrella term for a range of data structures, including Keyed collections: Maps, Sets, WeakMaps, WeakSetsThese data structures take object references as keys.
The difference between You could implement Usually, to bind data to a DOM node, one could set properties directly on the object, or use Structured data: JSONJSON (JavaScript Object Notation) is a lightweight data-interchange format, derived from JavaScript, but used by many programming languages. JSON builds universal data structures. See JSON and More objects in the standard libraryJavaScript has a standard library of built-in objects. Please have a look at the reference to find out about more objects. Determining types using the typeof operatorThe Please read the reference page for more details and edge cases. See alsoWhat are the 8 data types in JavaScript?The set of types in the JavaScript language consists of primitive values and objects.. Primitive values (immutable datum represented directly at the lowest level of the language) Boolean type. Null type. Undefined type. Number type. BigInt type. String type. Symbol type.. Objects (collections of properties). What are 3 types of data in JavaScript?JavaScript allows you to work with three primitive data types: numbers, strings of text (known as “strings”), and boolean truth values (known as “booleans”). JavaScript also defines two trivial data types, null and undefined, each of which defines only a single value.
How many data types in JavaScript show with example?There are two types of data types in JavaScript.
...
JavaScript primitive data types.. Which datatype is used in JavaScript?JavaScript Data Types. |