Ability to only check specific errors

Search Terms

specific errors ignore whitelist enable only

Suggestion

Ability to specify what errors you would like to see caught in the tsconfig.json. Errors not in the whitelist would be ignored.

Use Cases

Migrating large projects to Typescript. If the migration is done in a by-error-type approach you can't turn type-checking on in CI until all problems are fixed, which can take a long time when there is other work to do.

Examples

{
  "whitelistErrors": [7017, 2322, 2344]
}

Errors other than TS7017, TS2322, TS2344 would be ignored.

This suggestion is the inverse of https://github.com/microsoft/TypeScript/issues/29950

You can see an example of the opposite (blacklist errors) here: https://github.com/evolution-gaming/tsc-silent

Pytype, google's type-checker for python, also has the ability to blacklist specific errors.

# Comma separated list of error names to ignore.
disable =
    attribute-error

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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Note that this might lead to bad practice where developers lazily only check for certain errors rather than fixing their broken types. Using this feature should be discouraged unless used as a temporary measure for migrating from JS projects.

Start by reviewing how tsconfig.json options are handled and compare this proposal with the inverse behavior discussed in issue #29950. The issue describes a whitelist of diagnostic codes for TypeScript checking; done would mean non-whitelisted errors are ignored without changing emitted JavaScript, with the behavior covered by compiler tests.