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Ask questionsEmpty object is valid for non exact type annotation

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Flow version: 0.128.0

Expected behavior

Type error

Actual behavior

const someObj: { id: number } = {};
const num: number = someObj.id;
console.log(num);

num here is undefined, and definitely not a number

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  • Link to Try-Flow or Github repo: https://flow.org/try/#0PQKgBAAgZgNg9gdzCYAoAxnAdgZwC5g5wC2ApgPIBGAVgFxgDeYAlgCb1YCuxlpATmAC+YALyNBAbgzZ8YLsQ7deAsUTJVqAOjYSgA
facebook/flow

Answer questions dsainati1

Agreed. We have wanted to get rid of unsealed objects for a while, the difficulty is devising a new way to support the existing pattern of building up an object over time.

useful!

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