Revision 71305 of Glossary

  • Revision slug: JavaScript/Glossary
  • Revision title: Glossary
  • Revision id: 71305
  • Created:
  • Creator: Maian
  • Is current revision? No
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Revision Content

{{template.JSRef()}}

actual argument
A value that is passed to a function during a function call. When an object is passed, it is passed as an object reference. See also formal argument.
anonymous function
A function without a function name.
array
A sequence of values. An array is an Array object. Sometimes, the term "array" is used to refer to an object that has array-like qualities, namely it has numerical property names and a length property.
argument
An input to a function. Primitive arguments are passed "by value" - they are sent as copies to the function. Object arguments are passed "by reference" - an object reference to the object is sent to the function.
boolean
A primitive with two possible values: true and false. The Boolean object is a wrapper around a boolean primitive.
call
See function call.
closure
code
The source code that is written by the programmer.
constant
constructor
convert
When used in the context of primitive to object or object to primitive conversions, a typecast.
compile
A synonym for parse, when JavaScript is to be interpreted by an engine.
compile time
The time from when the program is first loaded and until the program is parsed.
datatype
deep copy
derive
Document Object Model (DOM)
An API for XML and HTML documents. The DOM is not part of JavaScript. JavaScript scripts within browsers have a binding to the DOM, whereby JavaScript can call DOM methods and otherwise interact with the DOM, and window is the global object.
engine
The JavaScript engine is an interpreter that parses and executes a JavaScript program.
error
An exception. Syntax error's are explictly specified as "syntax errors".
exception
execute
To carry out a programming instruction. Happens during runtime.
expression
formal argument
A placeholder within a function that is assigned an actual argument during a function call. A formal argument acts as a variable local to the function.
function
A body of code that can be called by other code or by itself, or a variable that refers to the function. When a function is called, arguments are passed to the function as input, and the function can optionally return an output. A function is also an object. See Functions.
function call
An execution of a function's code. A function is passed
function declaration
function expression
function name
An identifier that is declared as part of a function declaration or function expression. The scope this identifier is in depends on whether it is a declaration or expression.
global object
global scope
global variable
A variable in global scope. Such a variable is a property of the global object.
identifier
A sequence of characters in the code that identifies a variable, function, or property. Identifiers must start with a letter, "$", or "_", and can contain alphanumerical characters, "$", and "_". An identifier differs from a string in that a string is data, while an identifier is part of the code. In JavaScript, there is no way to convert identifiers to strings, but it is possible to parse strings into identifiers in certain cases.
implement
immutable
infinity
A number value representing infinity. See Infinity.
inner function
A function within another function, which in turn is denoted as an outer function.
instance
An object created by a constructor is an instance of that constructor.
internal
An object or data that cannot be directly accessed and operated on by the program, yet is necessary for the program's execution.
interpret, interpreter
See execute.
list
See array.
local, local scope
A variable or formal argument is local to a scope.
local variable
A variable that is in local scope.
method
A function that is a property of an object. Since functions themselves are objects, a method is actually an object reference to a function.
mutable
NaN
A number value representing Not-a-Number. See NaN.
null
number
A primitive with the value of a real number. Specifically, it has a double precision floating point value. The Number object is a wrapper around a number primitive.
object
In the context of a constructor, an instance of that constructor. Otherwise, an unordered collection of properties. To be more specific, an object is an associative array, where the keys are property names, and the values are property values. All objects are derived from Object, including arrays, and Object itself is also an object.
object-oriented programming (OOP)
A paradigm in which data is encapsulated within objects and the object itself is operated on, rather than its constituent parts. JavaScript is heavily object-oriented. It follows a prototype-based model.
object reference
A link to an object. Object references can be used as if they were the objects they link to. The concept of object references arises when assigning the same object to more than one property. Each assigned property does not hold a copy of the object. Instead, they hold object references that link to the same object. In practice, this means that if the object is modified, all properties referring to the object reflect the modification.
operand
operator
outer function
A function containing a function, which in turn is denoted as an inner function.
parameter
See argument.
parent object
The object a property is the property of.
parse, parser
To analyze and convert the program into an internal format which the JavaScript engine can work upon efficiently. In JavaScript, this is done during compile-time. and in certain cases where the parser is invoked, such as during a call to the eval method.
pass
Inputting to a function during a function call, e.g. an argument is passed to a function.
primitive, primitive value
A data that is not an object and does not have any methods. JavaScript has 5 primitive datatypes: string, number, boolean, null, undefined. With the exception of null and undefined, all primitives values have object equivalents which wrap around the primitive values, e.g. a String object wraps around a string primitive. All primitives are immutable.
program
The whole code to be interpreted and executed. can't think of a good layman's definition that's still relevant to JS...
property
Part of an object. A property has a name and a value. The name is a string. The value can a primitive, method, or object reference. It is often stated that a property holds an object - this is shorthand for saying the property holds a reference to the object, as properties cannot directly hold the objects themselves. In the case of the property holding an object, there is a distinction between the property's value and the object due to the nature of object references - the property's value can be changed when it's set to another value, but this does not modify the previously referred object in any way.
prototype
recursion
An act of a function calling itself.
regular expression, regexp
reference
In the context of objects, an object reference. Otherwise, the JavaScript reference itself.
run
See execute.
runtime
Everything after compile-time.
scope
script
A synonym for program, typically used when JavaScript is embedded within a document.
statement
string
A primitive with an immutable sequence of characters as its value. The String object is a wrapper around a string primitive.
syntax
syntax error
type
See datatype.
typecast
undefined
A primitive value automatically assigned to just-declared variables and formal arguments for which there are no actual arguments.
value
In the context of data or an object wrapper around that data, the primitive value that the object wrapper contains. In the context of a variable or property, something that can be either a primitive or an object reference. can this be more clear?
variable
A placeholder where a value can be stored. In JavaScript, variables are actually properties. Variables are typically accessed through identifiers. See also global variable and local variable. can this be more clear?
wrapper, wrap
An object that contains a primitive and whose sole purpose is to provide methods and properties to operate on that primitive. The wrapper's toString method returns the primitive.

Revision Source

<p>
{{template.JSRef()}}
</p>
<dl><dt> actual argument</dt><dd> A <b>value</b> that is <b>passed</b> to a <b>function</b> during a <b>function call</b>. When an <b>object</b> is passed, it is passed as an <b>object reference</b>. See also <b>formal argument</b>.
</dd></dl>
<dl><dt> anonymous function</dt><dd> A <b>function</b> without a <b>function name</b>.
</dd></dl>
<dl><dt> array</dt><dd> A sequence of values. An array is an <a href="en/JS/Array">Array</a> object. Sometimes, the term "array" is used to refer to an <b>object</b> that has array-like qualities, namely it has numerical property names and a <code>length</code> property.
</dd></dl>
<dl><dt> argument</dt><dd> An input to a <b>function</b>. <b>Primitive</b> arguments are <b>passed</b> "by value" - they are sent as copies to the function. <b>Object</b> arguments are passed "by reference" - an <b>object reference</b> to the object is sent to the function.
</dd></dl>
<dl><dt> boolean</dt><dd> A <b>primitive</b> with two possible values: true and false. The <a href="en/JS/Boolean">Boolean</a> object is a <b>wrapper</b> around a boolean primitive.
</dd></dl>
<dl><dt> call</dt><dd> See <b>function call</b>.
</dd></dl>
<dl><dt> closure</dt><dd> 
</dd></dl>
<dl><dt> code</dt><dd> The source code that is written by the programmer.
</dd></dl>
<dl><dt> constant</dt><dd> 
</dd></dl>
<dl><dt> constructor</dt><dd> 
</dd></dl>
<dl><dt> convert</dt><dd> When used in the context of <b>primitive</b> to <b>object</b> or object to primitive conversions, a <b>typecast</b>.
</dd></dl>
<dl><dt> compile</dt><dd> A synonym for <b>parse</b>, when JavaScript is to be <b>interpreted</b> by an <b>engine</b>.
</dd></dl>
<dl><dt> compile time</dt><dd> The time from when the program is first loaded and until the program is <b>parsed</b>.
</dd></dl>
<dl><dt> datatype</dt><dd> 
</dd></dl>
<dl><dt> deep copy</dt><dd> 
</dd></dl>
<dl><dt> derive</dt><dd> 
</dd></dl>
<dl><dt> Document Object Model (DOM)</dt><dd> An API for <a href="en/XML">XML</a> and <a href="en/HTML">HTML</a> documents. The <a href="en/DOM">DOM</a> is not part of JavaScript. JavaScript <b>scripts</b> within browsers have a binding to the DOM, whereby JavaScript can call DOM methods and otherwise interact with the DOM, and <a href="en/DOM/window">window</a> is the <b>global object</b>.
</dd></dl>
<dl><dt> engine</dt><dd> The JavaScript engine is an interpreter that <b>parses</b> and <b>executes</b> a JavaScript program.
</dd></dl>
<dl><dt> error</dt><dd> An <b>exception</b>. <b>Syntax error'</b>s are explictly specified as "syntax errors".
</dd></dl>
<dl><dt> exception</dt><dd> 
</dd></dl>
<dl><dt> execute</dt><dd> To carry out a programming instruction. Happens during <b>runtime</b>.
</dd></dl>
<dl><dt> expression</dt><dd> 
</dd></dl>
<dl><dt> formal argument</dt><dd> A placeholder within a <b>function</b> that is assigned an <b>actual argument</b> during a <b>function call</b>. A formal argument acts as a <b>variable</b> <b>local</b> to the function.
</dd></dl>
<dl><dt> function</dt><dd> A body of code that can be called by other code or by itself, or a <b>variable</b> that refers to the function. When a function is <b>called</b>, <b>arguments</b> are <b>passed</b> to the function as input, and the function can optionally <b>return</b> an output. A function is also an <b>object</b>. See <a href="en/JS/Functions">Functions</a>.
</dd></dl>
<dl><dt> function call</dt><dd> An execution of a <b>function'</b>s code. A function is <b>passed</b>
</dd></dl>
<dl><dt> function declaration</dt><dd> 
</dd></dl>
<dl><dt> function expression</dt><dd> 
</dd></dl>
<dl><dt> function name</dt><dd> An <b>identifier</b> that is declared as part of a <b>function declaration</b> or <b>function expression</b>. The <b>scope</b> this identifier is in depends on whether it is a declaration or expression.
</dd></dl>
<dl><dt> global object</dt><dd> 
</dd></dl>
<dl><dt> global scope</dt><dd> 
</dd></dl>
<dl><dt> global variable</dt><dd> A <b>variable</b> in <b>global scope</b>. Such a variable is a <b>property</b> of the <b>global object</b>.
</dd></dl>
<dl><dt> identifier</dt><dd> A sequence of characters in the code that identifies a <b>variable</b>, <b>function</b>, or <b>property</b>. Identifiers must start with a letter, "$", or "_", and can contain alphanumerical characters, "$", and "_". An identifier differs from a <b>string</b> in that a string is data, while an identifier is part of the code. In JavaScript, there is no way to convert identifiers to strings, but it is possible to <b>parse</b> strings into identifiers in certain cases.
</dd></dl>
<dl><dt> implement</dt><dd> 
</dd></dl>
<dl><dt> immutable</dt><dd> 
</dd></dl>
<dl><dt> infinity</dt><dd> A <b>number</b> value representing infinity. See <a href="en/JS/Infinity">Infinity</a>.
</dd></dl>
<dl><dt> inner function</dt><dd> A <b>function</b> within another function, which in turn is denoted as an <b>outer function</b>.
</dd></dl>
<dl><dt> instance</dt><dd> An <b>object</b> created by a <b>constructor</b> is an instance of that constructor.
</dd></dl>
<dl><dt> internal</dt><dd> An object or data that cannot be directly accessed and operated on by the program, yet is necessary for the program's execution.
</dd></dl>
<dl><dt> interpret, interpreter</dt><dd> See <b>execute</b>.
</dd></dl>
<dl><dt> list</dt><dd> See <b>array</b>.
</dd></dl>
<dl><dt> local, local scope</dt><dd> A <b>variable</b> or <b>formal argument</b> is local to a <b>scope</b>.
</dd></dl>
<dl><dt> local variable</dt><dd> A <b>variable</b> that is in <b>local scope</b>.
</dd></dl>
<dl><dt> method</dt><dd> A <b>function</b> that is a <b>property</b> of an <b>object</b>. Since functions themselves are objects, a method is actually an <b>object reference</b> to a function.
</dd></dl>
<dl><dt> mutable</dt><dd> 
</dd></dl>
<dl><dt> NaN</dt><dd> A <b>number</b> value representing Not-a-Number. See <a href="en/JS/NaN">NaN</a>.
</dd></dl>
<dl><dt> null</dt><dd> 
</dd></dl>
<dl><dt> number</dt><dd> A <b>primitive</b> with the value of a real number. Specifically, it has a double precision floating point value. The <a href="en/JS/Number">Number</a> object is a <b>wrapper</b> around a number primitive.
</dd></dl>
<dl><dt> object</dt><dd> In the context of a <i>constructor</i>, an <i>instance</i> of that constructor. Otherwise, an unordered collection of <b>properties</b>. To be more specific, an object is an associative array, where the keys are property names, and the values are property values. All objects are derived from <a href="en/JS/Object">Object</a>, including <b>arrays</b>, and Object itself is also an object.
</dd></dl>
<dl><dt> object-oriented programming (OOP)</dt><dd> A paradigm in which data is encapsulated within <b>objects</b> and the object itself is operated on, rather than its constituent parts. JavaScript is heavily object-oriented. It follows a <b>prototype</b>-based model.
</dd></dl>
<dl><dt> object reference</dt><dd> A link to an <b>object</b>. Object references can be used as if they were the objects they link to. The concept of object references arises when assigning the same object to more than one <b>property</b>. Each assigned property does not hold a copy of the object. Instead, they hold object references that link to the same object. In practice, this means that if the object is modified, all properties referring to the object reflect the modification.
</dd></dl>
<dl><dt> operand</dt><dd> 
</dd></dl>
<dl><dt> operator</dt><dd> 
</dd></dl>
<dl><dt> outer function</dt><dd> A <b>function</b> containing a function, which in turn is denoted as an <b>inner function</b>.
</dd></dl>
<dl><dt> parameter</dt><dd> See <b>argument</b>.
</dd></dl>
<dl><dt> parent object</dt><dd> The <b>object</b> a <b>property</b> is the property of.
</dd></dl>
<dl><dt> parse, parser</dt><dd> To analyze and convert the program into an internal format which the JavaScript engine can work upon efficiently. In JavaScript, this is done during <b>compile-time</b>. and in certain cases where the parser is invoked, such as during a call to the <a href="en/JS/eval">eval</a> method.
</dd></dl>
<dl><dt> pass</dt><dd> Inputting to a <b>function</b> during a <b>function call</b>, e.g. an <b>argument</b> is passed to a <b>function</b>.
</dd></dl>
<dl><dt> primitive, primitive value</dt><dd> A data that is not an <b>object</b> and does not have any methods. JavaScript has 5 primitive <b>datatypes</b>: <b>string</b>, <b>number</b>, <b>boolean</b>, <b>null</b>, <b>undefined</b>. With the exception of null and undefined, all primitives values have object equivalents which <b>wrap</b> around the primitive values, e.g. a <a href="en/JS/String">String</a> object wraps around a string primitive. All primitives are <b>immutable</b>.
</dd></dl>
<dl><dt> program</dt><dd> The whole code to be interpreted and executed. <span class="comment">can't think of a good layman's definition that's still relevant to JS...</span>
</dd></dl>
<dl><dt> property</dt><dd> Part of an <b>object</b>. A property has a name and a value. The name is a string. The value can a <b>primitive</b>, <b>method</b>, or <b>object reference</b>. It is often stated that a property holds an object - this is shorthand for saying the property holds a reference to the object, as properties cannot directly hold the objects themselves. In the case of the property holding an object, there is a distinction between the property's value and the object due to the nature of object references - the property's value can be changed when it's set to another value, but this does not modify the previously referred object in any way.
</dd></dl>
<dl><dt> prototype</dt><dd> 
</dd></dl>
<dl><dt> recursion</dt><dd> An act of a <b>function</b> calling itself.
</dd></dl>
<dl><dt> regular expression, regexp</dt><dd> 
</dd></dl>
<dl><dt> reference</dt><dd> In the context of <b>objects</b>, an <b>object reference</b>. Otherwise, the JavaScript reference itself.
</dd></dl>
<dl><dt> run</dt><dd> See <b>execute</b>.
</dd></dl>
<dl><dt> runtime</dt><dd> Everything after <b>compile-time</b>.
</dd></dl>
<dl><dt> scope</dt><dd> 
</dd></dl>
<dl><dt> script</dt><dd> A synonym for <b>program</b>, typically used when JavaScript is embedded within a document.
</dd></dl>
<dl><dt> statement</dt><dd> 
</dd></dl>
<dl><dt> string</dt><dd> A <b>primitive</b> with an <b>immutable</b> sequence of characters as its value. The <a href="en/JS/String">String</a> object is a <b>wrapper</b> around a string primitive.
</dd></dl>
<dl><dt> syntax</dt><dd>
</dd></dl>
<dl><dt> syntax error</dt><dd> 
</dd></dl>
<dl><dt> type</dt><dd> See <b>datatype</b>.
</dd></dl>
<dl><dt> typecast</dt><dd> 
</dd></dl>
<dl><dt> undefined</dt><dd> A <b>primitive</b> value automatically assigned to just-declared <b>variables</b> and <b>formal arguments</b> for which there are no <b>actual arguments</b>.
</dd></dl>
<dl><dt> value</dt><dd> In the context of data or an <b>object</b> <b>wrapper</b> around that data, the <b>primitive value</b> that the object wrapper contains. In the context of a <b>variable</b> or <b>property</b>, something that can be either a primitive or an <b>object reference</b>. <span class="comment">can this be more clear?</span>
</dd></dl>
<dl><dt> variable</dt><dd> A placeholder where a <b>value</b> can be stored. In JavaScript, variables are actually <b>properties</b>. Variables are typically accessed through <b>identifiers</b>. See also <b>global variable</b> and <b>local variable</b>. <span class="comment">can this be more clear?</span>
</dd></dl>
<dl><dt> wrapper, wrap</dt><dd> An <b>object</b> that contains a <b>primitive</b> and whose sole purpose is to provide <b>methods</b> and <b>properties</b> to operate on that primitive. The wrapper's <a href="en/JS/Object.prototype.toString">toString</a> method returns the primitive.
</dd></dl>
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