should follow tsconfig compilerOptions target when didn't pass target

[bluelovers]

let b;
export let a = b ??= true;

{
  "compilerOptions": {
    "target": "ES2019"
  }
}

---

this 2 should get same output

esbuild index.ts --tsconfig=./tsconfig.json --target=es2019
esbuild index.ts --tsconfig=./tsconfig.json

expected output

let b;
export let a = b !== null && b !== void 0 ? b : b = true;

[evanw]

I understand why this would be useful. However, different directories can take their settings from different tsconfig.json files with esbuild. In my opinion it would be confusing and error-prone for the language target (which really only makes sense as a global setting) to vary per-directory, especially by default. So I think the current esbuild behavior of having to specify a global language target is actually less error-prone and more correct.

[DylanVann]

The recently merged behavior can be an issue when there are tsconfig.json files in node_modules.

e.g.

I'm bundling some code that uses subscriptions-transport-ws which contains a tsconfig.json file that specifies "target": "es5". This results in errors like error: Transforming const to the configured target environment ("es5") is not supported yet.

Ideally I would like to totally ignore tsconfig.json files, and bundle/compile everything to the target I specify.