Coding convention

Which of the following is incorrect branch naming.

• Bugfix: bugfix/*

• Feature: feature/*

• Hotfix: hotfix/*

• Release: master/*

Answer explanation

Release: release/*

Which of the following is prefered function declaration?

• function test() {}

• const test = () => {}

import * as React from 'react'

• YES

• NO

Answer explanation

- This is the new convention for importing React: Introducing the New JSX Transform – React Blog

- Easier to upgrade and supports tree-shaking.

Which of the following is Function Declaration

• function Button(): React.ReactElement {/* */}

• const Button: React.FC = () => {/* */}

Answer explanation

- Globals are bad

- Explicit types over generalized ones

Always use React Fragment to render multiple React components over array and wrapper div:

1function ComponentA() {

return <>

<ComponentB />

<ComponentC />

</>

}

• YES

• NO

Answer explanation

- A React Fragment doesn’t create a HTML tag, it helps improve performance, and prevent bugs.

- Unlike array, a React Fragment doesn’t need to specify key prop to its children.

[Iterating objects] Which of the following statements are preferred?

• for (const x in someObj) { if (!someObj.hasOwnProperty(x)) continue;}

• for (const x in someObj) { }

• for (const x of Object.keys(someObj)) { }

• for (const [key, value] of Object.entries(someObj)) { }

someArr.forEach((item, index) => {

someFn(item, index);

});

• SHOULD

• SHOULD NOT

Answer explanation

Do not use Array.prototype.forEach, Set.prototype.forEach, and Map.prototype.forEach. They make code harder to debug and defeat some useful compiler checks (e.g. reachability).

export class Container

{

static FOO = 1;

static bar() { return 1; }

}

• SHOULD

• SHOULD NOT

Answer explanation

Best practice:

export const FOO = 1;

export function bar() { return 1; }

Number(''), Number(' '), Number('\t') would return 0 instead of NaN. 

• YES

• NO

Which of the following are defined in the coding convention

• //TODO

• //FIXME

• //ENHANCELATER

• //REFACTORLATER