Initializers are not allowed in ambient contexts error when installing Blueprint

The problem is that you are writing code in a d.ts file. You should only be writing types in these "ambient" files. Things like initializing variables, writing functions, etc should not be done in "ambient" files.

As of @blueprintjs/[email protected], Blueprint is now compiled using TypeScript 2.1. With this new version of TypeScript, initializers are added to the emitted typings for constants.

So before, a line of the emitted classes.d.ts looked like this:

export declare const ACTIVE: string;

It now looks like this and includes an initializer:

export declare const ACTIVE = "pt-active";

This new syntax in declaration files makes old versions of the compiler unhappy. To make the error go away, you'll need to make sure you're compiling your project with at least TypeScript 2.1.