Javascript

Decimal Error solution

tofix() let result = (0.1 + 0.2).toFixed(2); // '0.30' Number(result);
Math.round() Math.round(20.49); // 20 Math.round((0.1 + 0.2) * 10) / 10;

Display color log

  Reset = "\x1b[0m"
  Bright = "\x1b[1m"
  Dim = "\x1b[2m"
  Underscore = "\x1b[4m"
  Blink = "\x1b[5m"
  Reverse = "\x1b[7m"
  Hidden = "\x1b[8m"

  FgBlack = "\x1b[30m"
  FgRed = "\x1b[31m"
  FgGreen = "\x1b[32m"
  FgYellow = "\x1b[33m"
  FgBlue = "\x1b[34m"
  FgMagenta = "\x1b[35m"
  FgCyan = "\x1b[36m"
  FgWhite = "\x1b[37m"

  BgBlack = "\x1b[40m"
  BgRed = "\x1b[41m"
  BgGreen = "\x1b[42m"
  BgYellow = "\x1b[43m"
  BgBlue = "\x1b[44m"
  BgMagenta = "\x1b[45m"
  BgCyan = "\x1b[46m"
  BgWhite = "\x1b[47m"

Example: console.log('\u001b[32m\u001b[1m Login user: %d\u001b[0m ', rows.length);

Log type

  console.log("Log Info");    
  console.info("Info Info");      
  console.warn("Warn Info");      
  console.error("Error Info");

Log with variable

var cats = 2;
var dogs = 5;
console.log('%d cats and %d dogs', cat, dog);

sting to int

parseInt(sting)

Check object

if ( typeof yourVariable === 'object' && !Array.isArray(yourVariable) && yourVariable !== null ) { executeSomeCode(); }

Don't use eval function

you can use other functions instead of eval function.

var key = 'a';
using eval
eval('a') = 1;
using window
window[key] = 1;

var tiger = {}
tiger['age'] = 2;
var age_key = 'age';
tiger[age_key] = 2;

console.log with time

(function() {
    var old = console.log;
    console.log("> Log Date Format DD/MM/YY HH:MM:SS - UTCString");
    console.log = function() {
        var n = new Date();
        var d = ("0" + (n.getDate().toString())).slice(-2),
            m = ("0" + ((n.getMonth() + 1).toString())).slice(-2),
            y = ("0" + (n.getFullYear().toString())).slice(-2),
            t = n.toUTCString().slice(-13, -4);
        Array.prototype.unshift.call(arguments, "[" + d + "/" + m + "/" + y + t + "]");
        old.apply(this, arguments);
    }
})();

setTimeout (run function after 1 second)

setTimeout(function(){
  ...code
}, 1000);

set defualt parameter value in function

function(param1, param2= default value){}

current time

1. 현재 날짜 구하기

let today = new Date();

console.log(today);

2. 현재 날짜 년-월-일 포맷으로 구하기

let today = new Date();

 

// 년도 getFullYear()

let year = today.getFullYear(); 

// 월 getMonth() (0~11로 1월이 0으로 표현되기 때문에 + 1을 해주어야 원하는 월을 구할 수 있다.)

let month = today.getMonth() + 1

// 일 getDate()

let date = today.getDate(); // 일

 

console.log(year + '-' + month + '-' + date);

3. 현재 시 : 분 : 초 

let today = new Date();

 

// 시 getHours()

let hours = today.getHours();

// 분 getMinutes()

let minutes = today.getMinutes();

/// 초 getSeconds()

let seconds = today.getSeconds();

console.log(hours + ' : ' + minutes + ' : ' + seconds);

get full time

yes no confirm

if (confirm('Are you sure you want to save this thing into the database?')) { // Save it! console.log('Thing was saved to the database.'); } else { // Do nothing! console.log('Thing was not saved to the database.'); }

sync async function in for statument

for (var i = 0; i < 10; i++){
  console.log(i);
  (function(i){
    console.log(i);
  })(i);
}

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