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Node and The Senior Side Flashcards

1
Q

What is a code block? What are some examples of a code block?

A

In JavaScript, blocks are denoted by curly braces {} , for example, the if else, for, do while, while, try catch and etc.

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2
Q

What does block scope mean?

A

The context in which values and expressions are “visible” or can be referenced. If a variable or other expression is not “in the current scope,” then it is unavailable for use.

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3
Q

What is the scope of a variable declared with const or let?

A

let and const are blocked-scope,

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4
Q

What is the difference between let and const?

A

const is immutable, use it if you don’t plan on reassigning that variable

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5
Q

Why is it possible to .push() a new value into a const variable that points to an Array?

A

The const keyword ensures that the variable it creates is read-only. However, it doesn’t mean that the actual value to which the const variable reference is immutable. However, you cannot reassign a different value to the person constant like this. you’re not changing memory address.

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6
Q

How should you decide on which type of declaration to use?

A

If you plan on re-using it or not.

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7
Q

What is the syntax for writing a template literal?

A

Using a backtick character, which will produce a new string

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8
Q

What is “string interpolation”?

A

String formatting: the ability to substitute part of the string for the values of variables or expressions.

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9
Q

What is destructuring, conceptually?

A

The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.

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10
Q

What is the syntax for Object destructuring?

A

declare a variable, have open curly braces, if necessary, give a property name, but you can be concise and reference the property.

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11
Q

What is the syntax for Array destructuring?

A

a variable with open brackets, and more variables within the brackets being = array variable name. order matters

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12
Q

How can you tell the difference between destructuring and creating Object/Array literals?

A

The Order of assignment

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13
Q

What is the syntax for defining an arrow function?

A

A variable with a name with an assignment operator with an arrow function with a parameter and then curly braces

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14
Q

When an arrow function’s body is left without curly braces, what changes in its functionality?

A

it expects one expression and automatically returns that expression. implicit means implied.

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15
Q

How is the value of this determined within an arrow function?

A

Arrow functions have a lexical this and its value within the arrow function is determined by the surrounding scope.

Where the function is defined… where as previous it was call time.

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16
Q

What is a CLI?

A

Command-line-interface, processes commands via lines of text

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17
Q

What is a GUI?

A

Graphic user interface, aimed at consumers of technology

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18
Q

Use Case for Man

A

Man displays the on-line manual pages, you can specify sections with it.

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19
Q

Use case for Cat

A

reads files sequentially, writing them to the standard output. in the exercise we could read a text file

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20
Q

Use case for ls

A

list directory contents

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21
Q

use case for pwd

A

writes absolute path name

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22
Q

use case for echo

A

write arguments to the standard output. we wrote a string, console log for console

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23
Q

use case for touch

A

Change file access and modify items, create file

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24
Q

use case for mkdir

A

make directories

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25
use case for mv
move files or rename them
26
use case for rmman
remove directory files or directory with -r
27
Use case for cp
copy files or directories with -r
28
What are the three virtues of a great programmer?
laziness, impatience, and hubris
29
What is node.js
Allows to run javaScript outside the browser, commonly used to build back ends for web browsers, command-line programs, or any kind of automation that developers wish to perform.
30
What can Node.js be used for?
Node.js is designed to build scalable network applications, web application s that seamlessly and efficiently accommodate growth, and be designed with scalability in mind. Node.js can be used for everything, don't
31
What is a REPL?
Stands for, Read–eval–print loop, and it takes single user inputs, executes them, and returns the result to the user
32
When was Node.js created?
2009,
33
What back end languages have you heard of?
python, java, sql, javascript, ruby, Go, C++, C#, Rust, F#
34
What is a computer process?
is the instance of a computer program that is being executed by one or many threads. It contains the program code and its activity. A compute instance can be software or hardware which can run code, for example a CPU, GPU or a virtual machine
35
Roughly how many computer processes are running on your host operating system (Task Manager or Activity Monitor)?
365
36
Why should a full stack Web developer know that computer processes exist?
Because if it's extremely demanding, nobody will use your stuff. Plus the better optimized it is, the more people can use it.
37
What is the process object in a Node.js program?
global that provides information about, and control over, the current Node.js process.
38
How do you access the process object in a Node.js program?
you can explicity get it through require
39
What is the data type of process.argv in Node.js?
array
40
What is a JavaScript module?
a file containing related code
41
What values are passed into a Node.js module's local scope?
exports, module, the five
42
Give two examples of truly global variables in a Node.js program.
console, process, Object, undefined
43
What is the purpose of module.exports in a Node.js module?
So it can send out the data that's being return'd from the function
44
How do you import functionality into a Node.js module from another Node.js module?
call the local require() function
45
What is the JavaScript Event Loop?
It looks at the stack and the task queue, if the stack is empty, it takes the first thing in the queue and pushes it into the stack, which runs it allows us to async
46
What is different between "blocking" and "non-blocking" with respect to how code is executed?
blocking: code that is slow Blocking methods execute synchronously and non-blocking methods execute asynchronously.
47
What is a directory?
a file system structure that contains references to other computer files
48
What is a relative file path?
hierarchical path that locates a file or directory on a file system starting from the current directory
49
What is an absolute file path?
always contains the root element and the complete directory list required to locate the file. starts from the root/ or windows d
50
What module does Node.js include for manipulating the file system?
fs module
51
What method is available in the Node.js fs module for writing data to a file?
writeFile method
52
Are file operations using the fs module synchronous or asynchronous?
asynch
53
What is NPM?
it's a software registry, for open source devs to share or borrow packages.
54
What is a package?
A package is a file or directory that is described by a package.json file. A package must contain a package.json file in order to be published to the npm registry.
55
How can you create a package.json with npm?
Set up an account on npm, then use npm publish. Make sure your package.json is configured properly. npm innit -- yes
56
What is a dependency and how to you add one to a package?
Dependencies are specified in a simple object that maps a package name to a version range. The version range is a string which has one or more space-separated descriptors. Dependencies can also be identified with a tarball or git URL. To specify the packages your project depends on, you must list them as "dependencies" or "devDependencies" in your package's package.json file.
57
What happens when you add a dependency to a package with npm?
your package.json gets updated with the required semantics, to specify the packages your project depends on. Since it's a record. In node-modules, it has all the required files it depends on.
58
How do you add express to your package dependencies?
npm install express
59
What Express application method starts the server and binds it to a network PORT?
the listen method
60
How do you mount a middleware with an Express application?
Through the use method, include the two parameters res, or req
61
Which objects does an Express application pass to your middleware to manage the request/response lifecycle of the server?
A request object, which represents the incoming request. The second one is the response object, which represents the outgoing object. In general it's text information that doesn't pertain to any programming language. Express takes that data, parses it, and turns it into an object
62
What is the appropriate Content-Type header for HTTP messages that contain JSON in their bodies?
application/json
63
What does the express.json() middleware do and when would you need it?
to deal with the (incoming) data (object) in the body of the request.
64
What is the significance of an HTTP request's method?
It's ultimately how all clients and servers interact, regardless of platform, to simply boil it down, it's how the web works.
65
What is the significance of an HTTP request's method?
It's ultimately how all clients and servers interact, regardless of platform, to simply boil it down, it's how the web works.
66
What is PostgreSQL and what are some alternative relational databases?
a open source Relational Database Management System, it features ACID properties, automatically updatable views, materialized views, triggers, foreign keys, and stored procedures. Similar databases are microsoft server sql, mysql, and oracle database postgress can manage multiple database All based on the relational model of data,
67
What are some advantages of learning a relational database?
For a first time learner, it's a lot easier to know what is going on. Relational databases are arguably the most widely used kind of database. As for a database itself, it's a lot easier to scale, provides a set of tools (getting, updating), also a lot of them offer security features.
68
What is one way to see if PostgreSQL is running?
top or sudo service postgresql status
69
What is a database schema?
a collection of tables, schema defines how the data in a relational database should be organized. In the exercise pagalin was the schema.
70
What is a table?
Relational databases store data in relations, a list of rows each having the same set of attributes, in our case the actors, countries were all tables. "firstName", "lastName", and "dateOfBirth" attributes. also called columns
71
What is a row?
Describes the value of that attribute for that particular id, all rows have the same attributes.
72
What is SQL and how is it different from languages like JavaScript?
SQL is a declarative programming language.programmers describe the results they want and the programming environment comes up with its own plan for getting those results.
73
How do you retrieve specific columns from a database table?
Through using SELECT statement
74
How do you filter rows based on some specific criteria?
using WHERE statement
75
What are the benefits of formatting your SQL?
makes it easier to read, helps a lot for troubleshooting
76
What are four comparison operators that can be used in a where clause?
=, and != less than operator and greater than operator
77
How do you limit the number of rows returned in a result set?
using the limit statement
78
How do you retrieve all columns from a database table?
asterisk
79
How do you control the sort order of a result set?
using order by
80
How do you add a row to a SQL table?
insert statement
81
What is a tuple?
a list of values
82
How do you add multiple rows to a SQL table at once?
specifying more than one tuple of values, separated by commas.
83
How do you get back the row being inserted into a table without a separate select statement?
returning statement
84
How do you update rows in a database table?
use the update statement (classify table) | then set whatever row
85
Why is it important to include a where clause in your update statements?
so everything doesnt get updated
86
How do you delete rows from a database table?
delete statement, classify where with
87
How do you accidentally delete all rows from a table?
use the delete statement by itself
88
What is a foreign key?
A foreign key is a set of attributes in a table that refers to the primary key of another table. The foreign key links these two tables.
89
How do you join two SQL tables?
with the join statement, find the table where you want to join have the using keyword and select the attribute that's in both
90
How do you temporarily rename columns or tables in a SQL statement?
you can alias them by selecting the table name, have a dot, find its name under that table then use as word to assign it a new name.
91
What are some examples of aggregate functions?
AVG() – returns the average of a set. COUNT() – returns the number of items in a set. MAX() – returns the maximum value in a set. MIN() – returns the minimum value in a set. SUM() – returns the sum of all or distinct values in a set.
92
What is the purpose of a group by clause?
used to arrange identical data into groups with the help of some functions
93
What are the three states a Promise can be in?
pending: initial state, neither fulfilled nor rejected. fulfilled: meaning that the operation was completed successfully. rejected: meaning that the operation failed.
94
How do you handle the fulfillment of a Promise?
with the then method
95
How do you handle the rejection of a Promise?
with the catch method
96
What is Webpack?
Webpack is an open-source JavaScript module bundler. webpack allows you to specify parts of a website, specifically "static assets" into smaller bundles so that the site loads more efficiently. Now, in order to load the page, the browser has to make an individual request and response for each of those CSS files and JS files to retrieve, which wastes time. Webpack takes the files specified, combines them into one file, and then tries to shrink that one file down as much as it can by replacing variable names like "this_is_a_super_long_variable_name" to "a36".
97
How do you add a devDependency to a package?
You can add it manually or use npm install package --save-dev
98
What is an NPM script?
a convenient way to bundle common shell commands for your project. scripts are located in the package.json
99
How do you execute Webpack with npm run?
do npm run build "build was the property of the script"
100
How are ES Modules different from CommonJS modules?
outside of their different import and export syntax, ES Modules In CommonJS, require() is synchronous; it doesn't return a promise or call a callback. require() reads from the disk (or perhaps even from the network), and then immediately runs the script, they are dynamic. commonJS is from community In ESM, the module loader runs in asynchronous phases. In the first phase, it parses the script to detect calls to import and export without running the imported script. they are static. it's built in
101
What kind of modules can Webpack support?
ECMAScript modules. CommonJS modules. AMD (Asynchronous module definition) modules. WebAssembly
102
What does express.static() return?
middleware is software that sits in between two other pieces of software and performs some defined function. It allows the user to load the static files that are in the public directory:
103
What is the local __dirname variable in a Node.js module?
tells you the absolute path of the directory containing the currently executing file
104
What does the join() method of Node's path module do?
It returns a string with the complete normalized path containing all the segments.

Web Development (9 decks)

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