Javascript - General Concepts And Structures

Front 1

Name the five JavaScript primitives

Back 1

Numbers
Strings
Booleans
Null
Undefined

Front 2

Everything that isn't a primitive is an __________.

Back 2

Object

Front 3

Numbers, strings and booleans are object-like but are _______________.

Back 3

Immutable.

True objects, on the other hand, are mutable keyed collections.

Front 4

An object is a container of properties, which consist of __________ and ___________.

Back 4

A name and a value (and a value can be another object).

Front 5

Names of properties can be any string, including ___________.

Back 5

The empty string ''

Front 6

Object literals, using syntax:

var anObj ={
City: "Austin",
"State": "Texas"
}

allow you to define and create a new type of ___________

Back 6

Object

Front 7

Values can be retrieved in two ways:

Back 7

Using [ ] or the dot notation.
Eg,
anObj["propName"]
Or
anObj.propName (when name is a legal JS name)

Front 8

When an attempt is made to retrieve a nonexistent member, a value of _________ is produced.

Back 8

Undefined

Front 9

To fill in default values use the || operator as follows:

Back 9

var middle = stooge["middle-name"] || "none"

Front 10

To avoid a TypeError exception from trying to retrieve values from nonexistent properties, use the && operator as follows:

Back 10

flight.equipment && flight.equipment.model

Front 11

A value in an object can by updated--or added--by ___________________.

Back 11

Assignment

Front 12

Objects are passed around by _____________. They are never copied.

Back 12

Reference

Front 13

Every object is linked to at least one prototype object from which it can ______________________.

Back 13

Inherit properties

Front 14

The prototype link has no effect on ___________. When we make changes to an object, the object's prototype is not touched.

Back 14

Updating

Front 15

The prototype link is used only in __________. If we try to retrieve a property that the object lacks, JavaScript attempts to retrieve it from the prototype, repeating up the chain as needed.

Back 15

Retrieval

Front 16

Prototype relationships are _______. If we add a new property to a prototype, the property will immediately be visible to all objects based on that prototype.

Back 16

Dynamic

Front 17

For reflection, using the ___________ operator can be helpful in determining the type of a given property.

Back 17

typeof

Returns number, string, object, undefined, Boolean. (And null?)

Front 18

The _________________ method can determine if an object has a given property in and of itself and not from elsewhere on the prototype chain

Back 18

hasOwnProperty

Hint 18

flight.hasOwnProperty(c'constructor'). //false

Front 19

The for in statement can loop over all of the _________ _______ in an object--including ones that are ___________.

Back 19

Property names
Inherited

Front 20

There is no guarantee on the order of the property names in a ______ __ statement.

Back 20

for in

Front 21

To enumerate through properties in a certain order, first create a(n) ________ of the property names and then use an incremental _____ ________.

Back 21

Array
for loop

Front 22

The delete operator can remove a property from the object, but not from the ___________ _____________.

Back 22

Prototype linkage

Front 23

To minimize use of global variables, create a single global variable in which to "wrap" your _________ ___________.

Back 23

Entire Application

Eg,

var MYAPP = {};
MYAPP.x={
"first-name" : "moe",
lastName : "Howard"
};

Front 24

Functions enclose a set of statements and are used for code reuse, information hiding and composition. They define the _________ of objects.

Back 24

Behavior

Front 25

In JavaScript, functions are objects, and can be created using a __________ ___________.

Back 25

function literal. Eg,

var x = function (a,b) {

return a + b;

} ;

- OR -

var x = function optionalName(a,b){

return a+b;

};

Front 26

The four parts of a function literal are:

Back 26

1) the reserved word function

2) (optional) the function name

3) the set of parameters, wrapped in parentheses

4) a set of statements wrapped in curly braces. These are the body of the function

Front 27

Invoking a function _________ the execution of the current function, passing control and parameters to the new function.

Back 27

suspends

Front 28

In addition to the declared parameters, every function receives two additional parameters: _______ and _______.

Back 28

this and arguments

Front 29

The this parameter is important to OOP, and its value is determined by the _____________ ____________.

Back 29

invocation pattern

Front 30

There are four patterns of invocation in JavaScript:

Back 30

The method invocation pattern

The function invocation pattern

The constructor invocation pattern

The apply invocation pattern

They differ in how the bonus parameter this is initialized

Front 31

When a function is stored as a property of an object, we call it a ________.

Back 31

method

Front 32

Methods are members of an object. In method invocation, the this object is bound to the _____________ _________.

Back 32

containing object

Eg,

var myObject = {

value: 0;

increment: function(inc) {

this.value +=1;

}

Front 33

Methods that get their object context from this are called ______ _______.

Back 33

public methods

Front 34

When a function is not the property of an object, then it is invoked as a function, and its this is bound to the _______ object.

Back 34

global

(this feature is considered a mistake in the language design. A consequence is that a method cannot employ an inner function to help it due its work. There are workarounds, however.)

Front 35

A workaround to the global binding of functions is to pass the proper context to an inner function by specifying correct ________.

Back 35

Parameters.

Eg. (that.value1, that.value2), where "that" is defined as the previous this.

Front 36

JavaScript is a ________ inheritance language

Back 36

Prototypal. This means objects can inherit directly from other objects. The language is class-free.

Front 37

Despite being prototypal, JavaScript provides a ____________ pattern, reminiscent of classical languages.

Back 37

Constructor.

Eg,
var myQuo=new Quo("confused");

Front 38

Functions that are intended to be used with the _____ keyword are called constructors.

Back 38

new

Front 39

By convention, constructor functions are kept in variables with a ____________ name

Back 39

Capitalized.

Front 40

Use of conventional constructor functions is _____ _____________.

Back 40

Not recommended

Front 41

Because JavaScript is a functional object-oriented language, functions can have _________

Back 41

methods

Front 42

The __________ method lets us construct an array of arguments to use to invoke a function

Back 42

apply

eg,

var array = [3, 4];

var sum = add.apply(null, array);

Front 43

The __________ array is a bonus parameter that is available to functions when they are invoked

Back 43

arguments

This makes it possible to write functions that take an unspecified number of parameters. Use this cautiously, however.

Front 44

The _______ statement can be used to cause a function to return early (ie, instead of reaching the end of the statement block.)

Back 44

return

Front 45

A function always returns a value. If the return value is not specified, then ___________ is returned.

Back 45

undefined

Front 46

For handling ___________, JavaScript uses a try/catch mechanism similar to Java's, although with only one catch block.

Back 46

Exceptions

Front 47

JavaScript allows the basic types of the language to be ___________.

Back 47

Augmented.

Eg,

Function.prototype.method = function(name, func){

this.prototype[name]=func;

return this;

};

Front 48

A ____________ function is a function that calls itself, either directly or indirectly.

Back 48

recursive

Front 49

Scope in a programming language controls the _________ and ___________ of variables and paremeters

Back 49

Visibility,

Longevity

Front 50

JavaScript does not have block scope, even though its syntax suggests that it does. Instead it has ________ scope.

Back 50

Function

Front 51

Because of having function scope, it's recommended in JavaScript to declare all variables at the ____ of the function body, instead of where they are first used.

Back 51

top

Front 52

Each time an enclosed function is called, a new ________ is created.

Back 52

scope

Front 53

A closure is an expression--typically a function--that can have free variables together with an environment that ____those variables.

Back 53

binds

Front 54

A closure can be

1) The ____________ for a function, kept alive after the function has returned, or

2) A stackframe which is ____ _________ after the function returns.

Back 54

Not deallocated

Front 55

Callbacks are functions that are specified to be executed after a given function is finished. They are often used for ___________ processing

Back 55

asynchronous

Front 56

A module is a function or object that presents an interface but hides its state and implementation. It can eliminate the use of ____________.

Back 56

globals

Front 57

Cascading

Back 57

calling many methods (usually setters) on a single statement.

eg, getElement(x).move(a,b).height(14).color(red);

Front 58

The practice of remembering (caching) the results of previous costly operations for quick retrieval later.

Back 58

Memoization

Front 59

JavaScript, being loosely typed, never performs _________

Back 59

casts

Front 60

By convention, only __________ functions begin with a capital letter.

Back 60

constructor

(this avoids confusion and variable clobbering)

Front 61

__________ _________ can be used to construct an object when you don't remember the ________ __ ________.

Back 61

order of parameters

Front 62

JavaScript is conflicted about its ________nature.

Back 62

prototypal

Its prototype mechanism is obsucred by complicated syntax that looks vaguely classical.

Front 63

When a function object is created, the Function constructor runs code like this in the background:

Back 63

this.prototype = {constructor: this};

Front 64

Every function get a _________ object, because the language doesn't provide a way to determine which functions are to be used as _______________.

Back 64

prototype

constructors

Front 65

With a purely prototypal pattern, we dispense with _______ and focus instead on ____________.

Back 65

classes

objects

Front 66

__________ inheritance means customizing a new object by specifying its differences from the object on which it's based.

Back 66

Differential

Front 67

By being loosely typed, JavaScript has the benefit of being unconcerned about the lineage of classes. What matters is the object's _________.

Back 67

contents

Front 68

A true array is a _________ _______of memory in which elements are access by integers.

Back 68

linear allocation

Front 69

JavaScript "arrays" are merely objects with ____________ characteristics and ___________ methods.

Back 69

array-like

built-in

Front 70

Arrays created with brackets inherit from ________________. They also inherit a __________ property.

Back 70

Array.prototype

length

Front 71

With JavaScript arrays, the length can be _____________ augmented or reduced.

Back 71

dynamically

Front 72

Arrays created with curly braces inherit from _______________

Back 72

Object.prototype

Front 73

The _________ operator can remove elements from an array. The value changes to _____________.

Back 73

delete

undefined

Front 74

Array.splice() removes items from an array and adjusts the __________.

Back 74

indices

Front 75

Enumeration in JavaScript is generally best handled using the conventional ____ _____ and not the for in structure.

Back 75

for loop

Front 76

By adding a function to ________, every array inherits it.

Back 76

Array.prototype

Front 77

JavaScript borrows its Regular Expression features from ______.

Back 77

Perl

Front 78

The methods that work with JavaScript regular expressions are:
regexp.exec

regexp.test

string.match

string.replace,

__________

and ____________.

Back 78

string.search

string.split

Front 79

In JavaScript, regular expressions must be entered on a _________ _____.

Back 79

single line

Front 80

The RegExp object has the following built-in properties:

Back 80

global

ignoreCase

lastIndex (index at which to start)

multiline

source

Front 81

A RegExp class is a set of ___________.

Back 81

characters

Front 82

A RegExp factor is a character, character group, or _________ __________.

Back 82

escape sequence

Front 83

A RegExp sequence is one or more __________.

Back 83

factors

Front 84

A RegExp choice is one or more __________

Back 84

sequences

Front 85

A regExp group can be capturing, non-capturing, positive lookahead, or __________ ___________.

Back 85

negative lookahead.

Front 86

To designate capturing, put the regexp choice in ____________.

Back 86

parentheses

Front 87

The Array.concat(item...) method makes a ____ _______

Back 87

new array

(out of the items)

Front 88

The Array.join(separator) method makes a ___________ from an array

Back 88

String

Front 89

Array.pop() ________ and returns the last element.

Back 89

removes

Front 90

Array.push() appends items to the ____.

Back 90

end

Front 91

Array.shift() removes the _________ element and returns it.

Back 91

first

Front 92

Array.slice() makes a _________ _____ of an array

Back 92

shallow copy

Front 93

Array.sort sorts an array _________, even with numerals.

Back 93

alphabetically

Front 94

True or False:
Array.splice(start,deleteCount, item...) deletes elements from an array

Back 94

True

Front 95

Array.unshift() shoves items on to the _______.

Back 95

front

Front 96

The Function object has only one built-in method whose signature is ________.

Back 96

apply(thisArg, argArray).

"thisArg" specifies the object to be bound to this.

Front 97

The Number object has four built-in methods:

toExponential(fractionDigits)

toFixed(fractionDigits)

toPrecision(precision)

and

______________

Back 97

toString(radix), where radix is the base (default 10)

Front 98

The Object object has one built-in method:

Back 98

hasOwnProperty(name)

Front 99

RegExp has two built-in methods:

__________

and

___________

Back 99

exec(String)

test(String)

Test is simple and fast and returns true or false

Front 100

The String object has more than 14 _______ _______

Back 100

built-in methods

Front 101

Since JavaScript has no linker, all compilation units are loaded into a common ________ _______.

Back 101

global object

Front 102

The values 0, NaN, '', false, null and undefined are all considered "falsy", but they are ____ ___________.

Back 102

not interchangeable

Front 103

JavaScript has a function expression as well as a function ________.

Back 103

statement

Front 104

In JavaScript you can assign a variable name to an unnamed ________.

Back 104

function.

eg,
var f = function (){
};

Front 105

JSLint and JSHint are tools for _________ your JavaScript code

Back 105

testing

Front 106

JSON, or JavaScript Object Notation, is a lightweight _______ ________ _________.

Back 106

data interchange format.

Front 107

Always use _________ to declare variables, except when intentionally create a global.

Back 107

var

Front 108

When comparing objects, always use the ____ operator instead of the ___ operator.

Back 108

===

==

Front 109

An IIFE, or immediately invoked function expression is sometimes known as a SEAF, or _____________,

Back 109

self-executing anonymous function

Front 110

IIFEs are variations on anonymous functions. They are wrapped in parentheses and appended with any necessary __________.

Back 110

arguments

Front 111

A closure lets you capture the value of a passed-in variable at the moment it is passed in---no matter what happens to that variable in the __________ _______.

Back 111

outer scope

Front 112

Closures are also JavaScript's way of implementing _____________.

Back 112

encapsulation

Front 113

When defining a standalone function (ie, one not bound to any object), the this variable is bound to the __________ namespace.

Back 113

Global.

This can be circumvented conventionally by assigning the method's this variable to an intermediate that variable.

Front 114

In javaScript, objects inherit directly from _______ __________.

Back 114

Other objects

Front 115

JavaScript, being loosely typed, never ______.

Back 115

Casts