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compilerOptions support TDZ error option #33576

@kyle7zhang

Description

@kyle7zhang

According to the PR of #32221 , to prevent such problem like:

(function () {
    function cleanup() {
        console.log(A); // throw error
    }

    cleanup();
    const A = 1;
}());

this snippet will compile into:

(function () {
    function cleanup() {
        console.log(A); // log undefined
    }
    cleanup();
    var A = 1;
}());

Error in the first snippet will be ignored, and cause TDZ error. Can tsc support TDZ error enabled option like babel-plugin-transform-block-scoping ? It will notify peoples who write such pattern to prevent further weird problems.

Checklist

My suggestion meets these guidelines:

  • This wouldn't be a breaking change in existing TypeScript/JavaScript code
  • This wouldn't change the runtime behavior of existing JavaScript code
  • This could be implemented without emitting different JS based on the types of the expressions
  • This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
  • This feature would agree with the rest of TypeScript's Design Goals.

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