Quick Fix: Infer parameter types from usage … for one function

Search Terms

• 7043
• 7044
• better type may be inferred from usage

Suggestion

There's a quickfix to infer types from usage for variables that are implicitly any:

The two options are both useful, but for a large file the "Infer all types from usage" option feels a bit extreme. But inferring symbol-by-symbol can get tedious.

I'm proposing a middle ground option, something like "Infer all types in this block."

Use Cases

Adding type annotations to variables in large files based on usage piecemeal.

Examples

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.

No files, tests, or entry points are named in the issue. Start by reviewing the existing quickfixes for inferring types from usage and determine how a block-scoped variant should select symbols; done means the new option infers types for the intended block without changing emitted JavaScript.