Safe for ... in

[jclaveau]

Yesterday, during a review, a coworker asked me to replace this:

for (const prop in myJsonObject) {
    //...
}

by

  return myJsonObject.map((row: object) => {
    return Object.fromEntries(
      Object.entries(row).map(([key, value]) => {
          // return [key, values]
      })
    );
  });

or

  return myJsonObject.map((row: object) => {
    return Object.entries(row).reduce((acc, [key, value]) => {
      // return { ...acc, [key]: value };
    }, {});
  });

To avoid eslint complains due to https://eslint.org/docs/latest/rules/guard-for-in

Which, is factually safer but, IMHO, reduces too much the readability.

As a tradeoff I wrote this little function which may be interesting to find in Radash

export type ForInCallback<T> = (key: string, value: T) => T;

// eslint-disable-next-line @typescript-eslint/no-explicit-any
export const forIn = (subject: object, callback: ForInCallback<any>): object => {
  return Object.fromEntries(
    Object.entries(subject).map(([key, value]) => {
      return [key, callback(key, value)]
    })
  )
}

// Usable like
forIn (rowCopy, (prop, value) => {
    return value
})

Also investigating performances difference between fromEntries() + entries() + map() VS map() + entries() + reduce() VS for ... in + hasOwn()

[jclaveau]

Ooops, I just found https://radash-docs.vercel.app/docs/object/map-entries