npm

Question 1

What is NPM?

Answer 1

software registry where open source developers can share and borrow packages

consists of website, command line interface (CLI), and the registry

Question 2

What is a package?

Answer 2

a file or directory that is described by a package.json file that contains reusable code

Question 3

How can you create a package.json with npm?

Answer 3

npm init –yes

Question 4

What is a dependency and how to you add one to a package?

Answer 4

a dependency is a package that the project depends on

npm install

Question 5

What happens when you add a dependency to a package with npm?

Answer 5

package gets installed in a folder called node-modules and package.json is updated

Question 6

How do you add express to your package dependencies?

Answer 6

npm install express

Question 7

What Express application method starts the server and binds it to a network PORT?

Answer 7

app.listen(PORT, function)

Question 8

How do you mount a middleware with an Express application?

Answer 8

call a middleware method like app.use()

Question 9

Which objects does an Express application pass to your middleware to manage the request/response lifecycle of the server?

Answer 9

req and res

Question 10

What is the appropriate Content-Type header for HTTP messages that contain JSON in their bodies?

Answer 10

application/json

Question 11

What does the express.json() middleware do and when would you need it?

Answer 11

it parses incoming requests in json, used when incoming requests have json bodies

Question 12

What is the significance of an HTTP request’s method?

Answer 12

determines what action SHOULD be done with the given resource but programmer can make it do whatever
if empty code block, then httpie freezes for 30s

Question 13

What does express.static() return?

Answer 13

a middleware function preprogrammed to look in a directory and serve files

Question 14

What is the local __dirname variable in a Node.js module?

Answer 14

string of directory name of the current module (absolute path)

Question 15

What does the join() method of Node’s path module do?

Answer 15

joins path names

path.join('/foo', 'bar', 'baz/asdf', 'quux', '..');
// Returns: '/foo/bar/baz/asdf'

Question 16

What does fetch() return?

Answer 16

returns a promise for a response

Question 17

What is the default request method used by fetch()?

Answer 17

get

Question 18

How do you specify the request method (GET, POST, etc.) when calling fetch?

Answer 18

pass an object containing the method

https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#syntax

Question 19

When does React call a component’s componentDidMount method?

Answer 19

invoked immediately after a component is mounted (inserted into the tree)

Question 20

Name three React.Component lifecycle methods.

Answer 20

componentDidMount
componentDidUpdate
componentWillUnmount
constructor
render

Question 21

How do you pass data to a child component?

Answer 21

pass it as an argument props