Turns human readable breakpoints into correct mediaqueries.

This is particularly useful when working with window.matchMedia or when you work with CSS dinamically using JavaScript.

If you are using nodejs (but also browserify, webpack, etc...) you can simply use npm:

npm install mediaquery

then you can

var MQ = require('mediaquery');

By the way you if you are not using node, you may use bower

bower install mediaquery

then you can use it from window.MQ or require it using AMD

Assuming you have an object to describe the mediaqueries you need such as

var myMedias = {
  small: 300,
  medium: 600,
  tablet: 'tablet media query',
  big: 1024,
  huge: Infinity
};

Note that all the numerical values (Infinity included) will be automatically sorted in the correct order, while all the strings will be considered custome media queries; every other type of values will be stripped out.

So small: 300 means that my small media query will span from 0 to 300px, while medium will be from 301px to 600px; finally huge will go from 1025px to... Infinitely large screens.

If you do not specify an Infinity breakpoint a default breakpoint will be created spanning from the biggest available breakpoint to infinity.

You can use asObject to get back a similar object where the numbers for your breakpoints are substituted with correct mediaqueries.

e.g.

var MQ = require('mediaqueries');

MQ.asObject(myMedias);

will return

{
  small: 'screen and (max-width: 300px)',
  medium: 'screen and (min-width: 301px) and (max-width: 600px)',
  big: 'screen and (min-width: 601px) and (max-width: 1024px)',
  huge: 'screen and (min-width: 1025px)',
  tablet: 'tablet media query'
}

You can also have an array of couples ['name', 'mediaquery'] in output.

e.g.

MQ.asArray(myMedias);

will return

[
  ['small', 'screen and (max-width: 300px)'],
  ['medium', 'screen and (min-width: 301px) and (max-width: 600px)'],
  ['big', 'screen and (min-width: 601px) and (max-width: 1024px)'],
  ['huge', 'screen and (min-width: 1025px)'],
  ['tablet', 'tablet media query']
]

If you need to filter out the numerical breakpoints from a mixed object you can use getBreakPoints e.g.

MQ.getBreakPoints(myMedias);

will return

{
  small: 300,
  medium: 600,
  big: 1024,
  huge: Infinity // remember that Infinity is a number
}

In the same way you may need to filter out all the custom strings e.g.

MQ.getCustomQueries(myMedias);

will return

{
  tablet: 'tablet media query'
}