1.1.0 • Public • Published


Echo is a simple abstraction on top of console that provides a few nice APIs including:

  • Enabled/disable
  • Log rank
  • Colored output



$ bower i --save alianza-dev/echo#LATEST_SHA <-- put latest SHA there

$ npm i --save alianza-dev/echo#LATEST_SHA <-- put latest SHA there

If you want me to actually publish this on bower or npm, then upvote this issue


var options = {};
var name = 'networkLog';
// as global
var networkLog = Echo.create(name, options);
// or in CommonJS
var networkLog = require('echo').create(name, options);
// or in AMD
define(['path/to/echo.js', function(Echo) {
  var networkLog = Echo.create(name, options);


var stateLog = Echo.create('stateLog', {});
stateLog('Just like console.log');
stateLog.log('Just like console.log');'Just like console.log, except this is green now');
var networkLog = Echo.create('networkLog', {
  defaultColor: 'BYUBlue',
  colors: {
    BYUBlue: 'color:#001E4C',
    fuchsia: 'color:#FF0080'
networkLog('hey!'); // output in BYUBlue
typeof === 'undefined';
networkLog.log.BYUBlue('Go Cougars!');
networkLog.warn.fuchsia('Beware the power of pink!', {some: 'other stuff'});

Echo API

create(name:string, options:object)

Creates and registers a new echo logger and returns that instance.

name (required, string, undefined)

This is used to register the logger so you can retrieve it from Echo using Echo.get

options (required, object, undefined)

Used to control specifics of the instance of the echo. Properties are below:

rank (optional, number, 0)

Number from 0 to 5 inclusive that controls the level of logging. Logging rank is controlled by Echo.rank(newRank) // <-- getter/setter. A log will not go through to the logger (i.e. console) if the rank of the logger is too high (must be less than or equal to the Echo.rank).

defaultColor (optional, number, undefined)

This controls the color to any direct calls (not specifying a color).

colors (optional, object, pre-defined)

An object of styles to apply to the logger where the key is the method name (like green) and the value is a string of styles to be applied when it is invoked (like color:green).

enabled (optional, boolean, true)

Getter/setter to enable/disable the logger

logger (optional, object, console)

The logging instance to use. Probably don't need to use this...

logFns (optional, Array, pre-defined)

The functions that the given logger has that will be invoked.


Gets a registered echo by name from the given string. If no name is provided, then it returns the entire array.


Removes a registered echo by name from the given string. If no name is provided, then it removes all echos.


Rank getter/setter


Enabled getter/setter. When set to false, nothing will be logged no matter what!

echo API

Examples below assume: var echo = Echo.create('echo', {});


The returned logger from Echo.create is an alias to echo.log.

echo has all the logFns added to it as well. In the default configuration, these are: log, info, debug, warn, and error. All logFns are passed down into the provided logger (defaults to console) when this echo was created.

On top of this, each echo function has the keys to all the colors added to it as functions as well which will add the specified color value to the log to provide the desired color.

Query Params and window.echoLogging

You can enable/disable echos by name via query parameters or window.echoLogging. This is mostly useful for debugging purposes. Query params take priority, and disabled state takes priority. This also takes priority over whatever is passed into create.

window.echoLogging = {
  stateLog: false,
  networkLog: true
// url:,barLog&echoDisableLog=foobarLog,networkLog

The above state would result in fooLog, and barLog being enabled by default (overriding what was passed into create) and foobarLog, stateLog and networkLog being disabled by default.

Valid query parameters include:

  • echoEnableLog should be a list of echo names separated by commas
  • echoDisableLog should be a list of echo names separated by commas
  • echoRank should be a number between 0 and 5 - controls initial Echo.rank() state
  • echoEnabled should be "true" or "false" - controls initial Echo.enabled() state
  • echoAll should be "true" or "false" - if this is set, the initial enabled state for all loggers will be set to its value

In addition, echoRank, echoEnabled, and echoAll can all be set via the window.echoLogging variable.


Think of rank like this:

  • A high rank means that something is less critical to be logged.
  • A low rank means that it is more critical to be logged.



  • Only the first argument to the log functions will be colored
  • IE 10 doesn't support colors in the console, so Echo detects IE and doesn't attempt to add colors in IE.


  • Internet Explorer has issues with console and doesn't support all the operations that you may wish to (like debug for example). Echo will do an undefined check before invoking a logger function and call a noop instead).


I ran into a lot of trouble with loggers being re-registered with tests. Because I didn't want to spend time fixing the root problem (test context not being reset) you have testMode available which will prevent errors being thrown when an echo is registered with the same mode. Please only use this as a last resort. I'm not going to tell you how to do it. You'll have to figure it out if you feel like you really need to.


  • Write unit tests


npm i echo-logger

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  • kentcdodds