Remove Lodash dependency

[taneliang]

Currently, we're using Lodash as it's convenient. However, we want to be a good package with as few dependencies as possible. Lodash is not strictly necessary and should be replaced with plain util functions.

[liaujianjie]

Any thoughts on how to approach this? Writing our own utils?

[taneliang]

There’s a good chance we’ll be able to find them in the awesome https://github.com/you-dont-need/You-Dont-Need-Lodash-Underscore so thankfully we won’t have to write them ourselves :)