Tsoogle - like google but for your typescript project. Find functions or methods by approximate signature - return type, argument types or both. Supports optional arguments, rest arguments and partial type checking.
This is a vscode extension for the tsoogle project: https://github.com/stanimirovv/tsoogle
THIS IS A WORK IN PROGRESS PLUGIN.
That being said you can use Tsoogle if you run the Tsoogle Search command. The first time you run it for the session you will have to input your tsconfig filepath's absolute path. Then you can write queries (see the tsoogle repo for documentation)