"const" was transformed to "var" when target is "esnext"

[Roise-yue]

🔎 Search Terms

transform, const, var, target, ECMA, esnext

🕗 Version & Regression Information

• This is the behavior in every version I tried from Version 5.4 to Version 5.7.0-dev.20240904

⏯ Playground Link

No response

💻 Code

export const cilBlurLinear : string [ ] = [  ,  ] 
const [ ,  ] = cilBlurLinear;

🙁 Actual behavior

The JS code generated by tsc is as follows:

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.cilBlurLinear = void 0;
exports.cilBlurLinear = [,];
var ;

🙂 Expected behavior

“const” should be translated as "const" instead of "var", as the target in my configuration file is "esnext".

Additional information about the issue

tsconfig.json:

{
  "compilerOptions": {
    "target": "ESNext",
    "module": "esnext",
    "moduleResolution": "Node",
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "lib": ["es2023","dom"],
    "noEmitOnError":true,
    "force":true,
    "strict":true
  },
  "include": [
    "TScorpus/*"
  ],
  "exclude": [
    "node_modules"
  ]
}

[MartinJohns]

You are using the compiler wrong. You're calling the compiler by passing a list of filenames, in which case your local tsconfig.json is not being used and the compiler uses the default values for the compiler options.

If you call the compiler correctly, your code would not even compiler due to two errors:

• force is not a valid value for your tsconfig.json, it can only be used on the CLI together with --build.
• const cilBlurLinear : string [ ] = [ , ] is not valid with strictNullChecks enabled, because [,] contains undefined.

[Roise-yue]

You are using the compiler wrong. You're calling the compiler by passing a list of filenames, in which case your local tsconfig.json is not being used and the compiler uses the default values for the compiler options.

If you call the compiler correctly, your code would not even compiler due to two errors:

• force is not a valid value for your tsconfig.json, it can only be used on the CLI together with --build.
• const cilBlurLinear : string [ ] = [ , ] is not valid with strictNullChecks enabled, because [,] contains undefined.

Okay, I understand. I will modify the way I run the program.

[RyanCavanaugh]

We still shouldn't emit var; in ES5 though