Colors in JavaScript console

Question

Can Chrome\'s built-in JavaScript console display colors?

I want errors in red, warnings in orange and console.log\'s in green. Is that possible?

Answer 1

Check this out:

Animation in console, plus CSS

(function() {
  var frame = 0;
  var frames = [
    "This",
    "is",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!"
  ];
  var showNext = () => {
    console.clear();
    console.log(
      `%c `,
      "background: red; color: white; font-size: 15px; padding: 3px 41%;"
    );
    console.log(
      `%c ${frames[frame]}`,
      "background: red; color: white; font-size: 25px; padding: 3px 40%;"
    );
    console.log(
      `%c `,
      "background: red; color: white; font-size: 15px; padding: 3px 41%;"
    );
    setTimeout(
      showNext,
      frames[frame] === "SPARTA!" || frames[frame] === " " ? 100 : 1500
    );
    // next frame and loop
    frame++;
    if (frame >= frames.length) {
      frame = 0;
    }
  };
  showNext();
})();

https://jsfiddle.net/a8y3jhfL/

you can paste ASCII in each frame to watch an ASCII animation

Answer 2

In Chrome & Firefox (+31) you can add CSS in console.log messages:

console.log('%c Oh my heavens! ', 'background: #222; color: #bada55');

The same can be applied for adding multiple CSS to same command.

References

• MDN: Styling console output
• Chrome: Console API Reference

Answer 3

const coloring = fn => ({ background, color = 'white' }) => (...text) => fn(`%c${text.join('')}`, `color:${color};background:${background}`);
const colors = {
  primary: '#007bff',
  success: '#28a745',
  warning: '#ffc107',
  danger: '#dc3545',
  info: '#17a2b8',
};
const dir = (key = '', value = {}) => {
  logs.primary(`++++++++++++start:${key}++++++++++++++`);
  console.dir(value);
  logs.primary(`++++++++++++end:${key}++++++++++++++`);
};
const logs = Object.keys(colors)
  .reduce((prev, curr) => ({ ...prev, [curr]: coloring(console.log)({ background: colors[curr] }) }), { dir });
  
  logs.success('hello succes');
  logs.warning('hello fail');

Answer 4

If you want to color your terminal console, then you can use npm package chalk

npm i chalk

Answer 5

// log in color 
// consolelog({"color":"red","background-color":"blue"},1,2,3)

// consolelog({"color":"red"},1,2,3)
// consolelog(1,2,3)
function consolelog()
{
    var style=Array.prototype.slice.call(arguments,0,1)||["black"];
    var vars=(Array.prototype.slice.call(arguments,1)||[""])
    var message=vars.join(" ")
    var colors = 
        {
            warn:
                {
                    "background-color"  :"yellow",
                    "color"             :"red"
                },
            error:
                {
                    "background-color"  :"red",
                    "color"             :"yellow"
                },
            highlight:
                {
                    "background-color"  :"yellow",
                    "color"             :"black"
                },
            success : "green", 
            info    : "dodgerblue"  

        }
    var givenstyle=style[0];
    var colortouse= colors[givenstyle] || givenstyle;
    if(typeof colortouse=="object")
    {
        colortouse= printobject(colortouse)
    }
    if(colortouse)
    {
        colortouse=(colortouse.match(/\W/)?"":"color:")+colortouse;
    }
    function printobject(o){
        var str='';

        for(var p in o){
            if(typeof o[p] == 'string'){
                str+= p + ': ' + o[p]+'; \n';
            }else{
            str+= p + ': { \n' + print(o[p]) + '}';
            }
        }

        return str;
    }
    if(colortouse)
    {
        console.log("%c" + message, colortouse);
    }
    else
    {
        console.log.apply(null,vars);
    }
}
console.logc=consolelog;

Answer 6

To chain CSS3 styles which spans across multiple lines, you can do like this,

var styles = [
    'background: linear-gradient(#D33106, #571402)'
    , 'border: 1px solid #3E0E02'
    , 'color: white'
    , 'display: block'
    , 'text-shadow: 0 1px 0 rgba(0, 0, 0, 0.3)'
    , 'box-shadow: 0 1px 0 rgba(255, 255, 255, 0.4) inset, 0 5px 3px -5px rgba(0, 0, 0, 0.5), 0 -13px 5px -10px rgba(255, 255, 255, 0.4) inset'
    , 'line-height: 40px'
    , 'text-align: center'
    , 'font-weight: bold'
].join(';');

console.log('%c a spicy log message ?', styles);

Result

Find more :- https://coderwall.com/p/fskzdw/colorful-console-log

Cheers.