Consider adding noUncheckedIndexedAccess to tsconfig

[dylangrandmont]

Environment

• Package version(s): 4.x and 5.x
• Browser and OS versions: (Applied to all, and to TypeScript >= 4.1)

Feature request

The request is for blueprint to include "noUncheckedIndexedAccess": true in its tsconfig. The reasoning is as follows:

By default, TypeScript will not correctly infer when an array element can be undefined

  let g: Array<number> = []
  let h = g[0] // type of h is number

On ~recent release of TS (4.1) this behaviour can be changed via a configuration
microsoft/TypeScript#39560
https://www.typescriptlang.org/tsconfig#noUncheckedIndexedAccess

Unfortunately because blueprint ships tsx files directly, any library which uses blueprint as a dependency will be unable to set "noUncheckedIndexedAccess": true in its tsconfig.ts. Doing so will result in build time failures during the TypeScript compilation, for example

./node_modules/@blueprintjs/core/src/components/tree/tree.tsx:98:31
Type error: Type 'undefined' cannot be used as an index t
info  - Linting and checking validity of types .Failed to compile.

./node_modules/@blueprintjs/core/src/components/tree/tree.tsx:98:31
Type error: Type 'undefined' cannot be used as an index type.

     ): TreeNodeInfo<U> {
         if (path.length === 1) {
             return treeNodes![path[0]];
                               ^
         } else {
             return Tree.nodeFromPath(path.slice(1), treeNodes![path[0]].childNodes);
         }

[adidahiya]

Unfortunately because blueprint ships tsx files directly

You shouldn't be pulling these files into your TS compilation pipeline. They are only there to provide accurate sourcemaps. Your tsc should only see (be given access to) the .d.ts files.

[dylangrandmont]

You shouldn't be pulling these files into your TS compilation pipeline. They are only there to provide accurate sourcemaps. Your tsc should only see (be given access to) the .d.ts files.

Thanks for the reply @adidahiya. I see I am inadvertently importing some types from @blueprintjs/core/src/components and this is my underlying issue.