├── .gitignore
├── .prettierrc
├── .eslintrc.json
├── README.md
├── package.json
├── NaN.js
└── NegativeZero.js


/.gitignore:
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1 | node_modules


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/.prettierrc:
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1 | {
2 |   "singleQuote": true
3 | }
4 | 


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/.eslintrc.json:
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1 | {
2 |   "extends": ["airbnb", "prettier"],
3 |   "plugins": ["prettier"],
4 |   "rules": {
5 |     "prettier/prettier": ["error"]
6 |   }
7 | }
8 | 


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/README.md:
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1 | # javascript-bits
2 | 
3 | [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com)
4 | 


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/package.json:
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 1 | {
 2 |   "name": "javascript-bits",
 3 |   "version": "1.0.0",
 4 |   "description": "",
 5 |   "main": "index.js",
 6 |   "scripts": {
 7 |     "lint": "eslint"
 8 |   },
 9 |   "keywords": [],
10 |   "author": "",
11 |   "license": "ISC",
12 |   "devDependencies": {
13 |     "eslint": "^6.1.0",
14 |     "eslint-config-airbnb": "^17.1.1",
15 |     "eslint-config-prettier": "^6.0.0",
16 |     "eslint-plugin-prettier": "^3.1.0",
17 |     "prettier": "^1.18.2"
18 |   }
19 | }
20 | 


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/NaN.js:
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 1 | // 1. NaN
 2 | 
 3 | const a = Number('n/a');
 4 | 
 5 | const b = 'a' - 'b';
 6 | console.log(a, b); // NaN NaN
 7 | 
 8 | // 1.1 The **ONLY** datatype which is not equal to itself
 9 | 
10 | console.log(a === a); // false
11 | console.log(a == a); // false
12 | 
13 | console.log(undefined === undefined); // true
14 | console.log(null === null); // true
15 | console.log(NaN === NaN); // false
16 | 
17 | // 1.2 Ways to find NaN (ES6)
18 | 
19 | // 1.2.1 - Older ways of finding NaN
20 | 
21 | console.log(isNaN(b)); // true
22 | 
23 | /* global isNaN checks whether the value is a valid Number or not. 
24 |     
25 |     The way it works is: 
26 |         1. First it coerce to Number
27 |         2. Then it checks, whether the passed value results in NaN
28 | 
29 |     In below example, "Hello Earth" String is coerced to Number which results in NaN. 
30 |     Hence it is true.
31 | 
32 |     TL;DR:  global isNaN checks for NaN after the input being coerced to number!
33 | */
34 | console.log(isNaN('Hello Earth!')); // true
35 | 
36 | // 1.2.2 - ES6 way of checking NaN
37 | 
38 | console.log(Number.isNaN(a)); // true
39 | 
40 | // 1.2.3 - Check two NaN
41 | 
42 | console.log(Object.is(b, a)); // true
43 | 
44 | // 1.2.4 - NaN check in ES6 way
45 | 
46 | console.log(Object.is('Hello Mercury!', NaN)); // false
47 | 
48 | console.log(Number.isNaN('Hello Sun!')); // false
49 | 


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/NegativeZero.js:
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 1 | // 2. Negative Zero (-0)
 2 | 
 3 | const a = -0;
 4 | 
 5 | // Negative Zero equals itself
 6 | console.log(a === -0); // true
 7 | 
 8 | // 2.1
 9 | // Irrespective of the sign, Negative equals to 0
10 | console.log(a === 0); // true
11 | 
12 | // 2.2
13 | // It is neither greater than nor less than that of 0
14 | console.log(a < 0); // false
15 | console.log(a > 0); // false
16 | 
17 | // 2.3
18 | // Ways to find -0
19 | // Object.is can determine whether the given value is -0 or not
20 | // Object.is results in false when -0 is checked with 0
21 | 
22 | console.log(Object.is(a, -0)); // true
23 | console.log(Object.is(a, 0)); // false
24 | 
25 | // 2.4
26 | // Math.sign helps to figure out the sign of the given number, results in 1 and -1 for positive and negative values respectively
27 | console.log(Math.sign(-5)); // -1
28 | 
29 | // 2.4.1
30 | // when it comes to 0 and -0, Math.sign works differently
31 | console.log(Math.sign(0)); // 0
32 | console.log(Math.sign(-0)); // -0
33 | 
34 | // 2.4.2
35 | // helper function to get sign
36 | const getSign = value => {
37 |   return value !== 0 ? Math.sign(value) : Object.is(value, -0) ? -1 : 1;
38 | };
39 | 
40 | console.log(getSign(0)); // 1
41 | console.log(getSign(-0)); // -1
42 | console.log(getSign(-5)); // -1
43 | 
44 | // 2.4.3
45 | // Infinity
46 | // (Number / 0) results in Infinity
47 | // (Number / -0) results in -Infinity
48 | 
49 | console.log(1 / 0); // Infinity
50 | console.log(1 / -0); // -Infinity
51 | 
52 | // This is one of the best solution to find -0 ( to impress your friends 😜 )
53 | 
54 | const isNegativeZero = value => {
55 |   return value === 0 && 1 / value === -Infinity;
56 | };
57 | 
58 | console.log(isNegativeZero(-0)); // true
59 | console.log(isNegativeZero(0)); // false
60 | console.log(isNegativeZero(-5)); // false
61 | 
62 | // 2.5
63 | // As like 0, -0 also coerce to false in terms of Boolean operation
64 | console.log(Boolean(0)); // false
65 | console.log(Boolean(-0)); // false
66 | 


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