Easy markup for react-transition-group

For when you don't feel like googling that weird pattern react-transition-group and its variants use every dang time.

Handles one or multiple class/id names, timings, and eases.

@import '../node_modules/scss-react-transition/scss-react-transition.scss';

@include transition('test #test2', (opacity: (0.01, 1), max-height: (0, 30px, 20px)), 150 0.1s, ease ease-out);

yields:

.test-enter, #test2-enter {
  opacity: 0.01;
  max-height: 0;
}

.test-enter.test-enter-active, #test2-enter#test2-enter-active {
  opacity: 1;
  max-height: 30px;
  transition: 150ms ease;
}

.test-exit, .test-leave, #test2-exit, #test2-leave {
  opacity: 1;
  max-height: 20px;
}

.test-exit.test-exit-active, .test-leave.test-leave-active, #test2-exit#test2-exit-active, #test2-leave#test2-leave-active {
  opacity: 0.01;
  max-height: 0;
  transition: 0.1s ease-out;
}

(It does both -exit and -leave for the out transitions because they changed the class names in the React 16 version.)

| Argument | Default value | Default unit | Required | | --------------- | ------------- | ------------------------- | -------- | | Classnames | none | string or list | yes | | Props | none | list | yes | | Transition time | 150ms | ms if unitless, accepts s | no | | Transition ease | ease | an ease type | no |

Intro animation only

Play only the intro animation by setting a property's third argument to null:

@include transition('introOnly', (transform: (translateY(-10px), initial, null)));

.introOnly-enter {
  transform: translateY(-10px);
}

.introOnly-enter.introOnly-enter-active {
  transform: initial;
  transition: 150ms ease;
}