breakpoint-changes-rx

Detect and handle viewport changes. Using RxJS Observables

You have a responsive web site and want to handle viewport state with ease?

Here we are. Handing viewport state with the help of RxJS.

import breakpoints, { parseBreakpoints } from 'breakpoint-changes-rx'
import style from './style.scss'

const breakpointDefinitions = parseBreakpoints(style)

const bps = breakpoints(breakpointDefinitions)

console.log('current breakpoints: %o', bps.getCurrentBreakpoints())

What are the current viewports?

console.log(
  breakpoints.getCurrentBreakpoints(), // [ "md", "lg" } ]
)

Install

yarn add breakpoint-changes-rx

breakpoints(breakpointDefinitions)

This function initializes the breakpoint detection and returns an object containing following properties:

• breakpoint-changes-rx
  • What are the current viewports?
  • Install
  • breakpoints(breakpointDefinitions)
    • breakpointsChanges$
    • breakpointsChangesBehavior$
    • getCurrentBreakpoints()
    • breakpointsChange(bp)
    • breakpointsInRange(range)
    • includesBreakpoints(bps)
    • includesBreakpoint(bp)
  • Configuration
    • Format
    • parseBreakpoints(object, config)
  • License

For details about the breakpointDefinitions see Configuration section

import breakpoints, { parseBreakpoints } from 'breakpoint-changes-rx'
import style from './style.scss'

const breakpointDefinitions = parseBreakpoints(style)

const bps = breakpoints(breakpointDefinitions)

console.log('current breakpoints: %o', bps.getCurrentBreakpoints())

breakpointsChanges$

An observable that emits a value when breakpoints change. The format of these values is

{
  curr: ['md'],
  prev: ['lg'],
}

Usage example:

bps.breakpointChanges$.subscribe(({
  curr,
  prev,
}) => {
  console.log('previous breakpoint is %o, actual breakpoint is %o', prev, curr)
})

Current and previous breakpoints are stored in arrays because it's possible to have multiple active breakpoints at the same time.

breakpointsChangesBehavior$

This is the same as breakpointsChanges$ except it is a BehaviorSubject. So when a new Observer subscribes it will immediately emit the current breakpoint data.

getCurrentBreakpoints()

Returns the current active breakpoints as an array.

const current = bp.getCurrentBreakpoints()

console.log('current breakpoints are %o', current) // e.g. ['lg']

breakpointsChange(bp)

Returns an observable that emits a boolean value when the given breakpoint gets entered or left.

bp.breakpointsChange('md').subscribe((active) => {
  console.log('breakpoint md %s', active ? 'entered' : 'left')
})

breakpointsInRange(range)

Returns an observable that emits a boolean value when a range of breakpoints gets entered or left. If a change appears between the given range no value gets emitted.

bp.breakpointsInRange(['sm', 'md']).subscribe((active) => {
  console.log('range gets %s', active ? 'entered' : 'left')
})

includesBreakpoints(bps)

Returns true if the current breakpoints contain breakpoints which are part of the given array.

console.log('this might be a mobile device %o', bp.includesBreakpoints(['sm', 'md']))

includesBreakpoint(bp)

Returns true if the given breakpoint is part of the current active breakpoints.

console.log('breakpoint "md" is active %o', bp.includesBreakpoint('md'))

Configuration

This section describes the configuration used by the breakpoints(breakpointDefinitions) function using this example

Format

The used format for this example is shown here:

{
  "sm": { "max": "767px" },
  "md": { "min": "768px", "max": "991px" },
  "lg": { "min": "992px", "max": "1199px" },
  "xl": { "min": "1200px" }
}

The values for the minand max properties can also be of type number. In this case pixels as unit will be omitted.

parseBreakpoints(object, config)

This function was created to parse breakpoint data from exported variables of a CSS Module.

:export {
  breakpoint-sm-max: $bp-small-max;
  breakpoint-md-min: $bp-medium;
  breakpoint-md-max: $bp-medium-max;
  breakpoint-lg-min: $bp-large;
  breakpoint-lg-max: $bp-large-max;
  breakpoint-xl-min: $bp-xlarge;
}

import { parseBreakpoints } from 'breakpoint-changes-rx'
import style from './style.scss'

const breakpointDefinitions = parseBreakpoints(style)

It filters all properties of the passed object that matches the breakpoint pattern.

This function can use an optional configuration.

License

MIT © 2023 Jens Simon