mastodon/app/javascript/mastodon/initial_state.js

const element = document.getElementById('initial-state');
const initialState = element && JSON.parse(element.textContent);

const getMeta = (prop) => initialState && initialState.meta && initialState.meta[prop];

export const reduceMotion = getMeta('reduce_motion');
export const autoPlayGif = getMeta('auto_play_gif');
export const unfollowModal = getMeta('unfollow_modal');
export const boostModal = getMeta('boost_modal');
export const deleteModal = getMeta('delete_modal');
export const me = getMeta('me');

export default initialState;