A way to expand mapped types

I want to be able to expand mapped type in intellisense

Currently, mapped types is displayed directly with the mapper and original type, which is unhelpful as hell

With the ts 2.8 condition type,
you can write more powerful declaration to map almost everything to correct type for you,
but the ide simply show it is mapped,
you don't know what is it actually mapped to.

for example, in the above case, I have a mapper looks like

type Mapper<T> = {
    [K in keyof T]: 
        T[K] extends {type: SQL_ENUM<infer U>}? U:
        T[K] extends {type: SQL_ENUM<infer U>, allowNull: true}? U | undefined:
        
        T[K] extends {type: typeof Sequelize.DATE, allowNull: true}? Date | undefined:
        T[K] extends {type: typeof Sequelize.DATE}? Date:

        T[K] extends {type: typeof Sequelize.INTEGER, allowNull: true}? number | undefined:
        T[K] extends {type: typeof Sequelize.INTEGER}? number:

        // stop here, fon't let things goes too wrong
        T[K] extends {type: typeof Sequelize.ENUM}? never:

        T[K] extends {type: typeof Sequelize.STRING, allowNull: true}? string | undefined:
        T[K] extends {type: typeof Sequelize.STRING}? string:

        T[K] extends {type: typeof Sequelize.TEXT, allowNull: true}? string | undefined:
        T[K] extends {type: typeof Sequelize.TEXT}? string:

        T[K] extends {type: typeof Sequelize.BOOLEAN, allowNull: true}? boolean | undefined:
        T[K] extends {type: typeof Sequelize.BOOLEAN}? boolean:

        any
}

that will transform the decalration to a simple

interface session {
    token: string,
    userId: string,
    ip: string
}

But the ide won't tell you anything, which is quite annoying

この issue の Mapper 例を再現として使用し、まず TypeScript の language-service におけるマップ型と条件型の IntelliSense 処理から着手します。表示されるマップ型が解決済みのプロパティをどのように公開すべきかを確認します。完了の条件は、IntelliSense が mapper と元の型だけでなく、展開された session の形状を提示することです。