What does the dollar prefix ($) mean in Vue.js?

What is the meaning of the dollar character/symbol prefix before property names in Vue.js?

For example: this.$emit('clicked', 'demo')

The use of the $ and _ prefixes in Vue are explained here:


Specifically in the Detailed Explanation section.

_ is for private instance properties:

Vue uses the _ prefix to define its own private properties...

$ is for public instance properties:

As for the $ prefix, its purpose within the Vue ecosystem is special instance properties that are exposed to the user...

Both are used to avoid collisions with property names chosen by component creators, such as props and data properties.