soapbox/app/soapbox/utils/normalizers.js

// Use new value only if old value is undefined
export const mergeDefined = (oldVal, newVal) => oldVal === undefined ? newVal : oldVal;

export const makeEmojiMap = emojis => emojis.reduce((obj, emoji) => {
  obj[`:${emoji.shortcode}:`] = emoji;
  return obj;
}, {});