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<!--info-header-start--><h1>Required Keys </h1><blockquote><p>by yituan <a href="https://github.com/yi-tuan" target="_blank">@yi-tuan</a></p></blockquote><p><a href="https://tsch.js.org/89/play" target="_blank"></a> &nbsp;&nbsp;&nbsp;<a href="./README.zh-CN.md" target="_blank"></a> <a href="./README.ja.md" target="_blank"></a> </p><!--info-header-end-->

Implement the advanced util type RequiredKeys<T>, which picks all the required keys into a union.

For example

ts
type Result = RequiredKeys<{ foo: number; bar?: string }>;
// expected to be “foo”
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