React Native

Question 1

components

Answer 1

small, isolated code blocks to determine render. When data changes, React updates+re-renders.

Question 2

React component class/type, parameters/properties(props),

Answer 2

a component which accepts props and returns a view hierarchy, displayed via its render().

Question 3

render()

Answer 3

description of what to see on screen; React takes, then displays result

Question 4

equivalent of JSX below in JS:
<div>
  <h1>Shopping List for {props.name}</h1>
  <ul>
    <li>Instagram</li>
    <li>WhatsApp</li>
    <li>Oculus</li>
  </ul>
</div>;

Answer 4

React.createElement(“div”, {
className: “shopping-list”
}, React.createElement(“h1”, null, “Shopping List for “, props.name), React.createElement(“ul”, null, React.createElement(“li”, null, “Instagram”), React.createElement(“li”, null, “WhatsApp”), React.createElement(“li”, null, “Oculus”)));

Question 5

how to respond to click in button?

Answer 5

pass in function for onClick prop.

    {this.props.value}

Question 6

=>

Answer 6

“arrow function”; lambdas

(param1, param2) => block; returnValue

Question 7

super

Answer 7

whenever defining constructor of subclass, call super(props)

Question 8

if you change state in component’s render(), …

Answer 8

React will re-render when state changes

Question 9

to change state, use

Answer 9

this.setState({comment: 'Hello World!'});
not
`this.state.comment = ‘Hello World!’

Question 10

state where?

Answer 10

lift state up

Question 11

state privacy

Answer 11

state is private to component which defined it

Question 12

controlled components

Answer 12

components where the render’s properties are fully set by props

Question 13

function components

Answer 13

for components that only render, replace render() with function

Question 14

ternary JS

Answer 14

var = ? “isTrue” : “isFalse”;

Question 15

mental model:

Answer 15

we build from components.
components take in props
components with state, initialize state, and change state thru functions.
state is private to a component, but can pass state to child components.
children can’t change parent’s state, but can be given handlers by parents, which they call, which leads a parent to affect that parent’s state.
render() in a component returns components that make up that component
can replace render with function that returns same as render
=> is lambda, where (params) => return+exec_block

Question 16

keys

Answer 16

specify list items