Regression - Array.filter

Bug Report

Array filter have possibly wrong signature or 4.8 introduced “Unconstrained Generics No Longer Assignable to {}” introduced type error

🔎 Search Terms

🕗 Version & Regression Information

After the update to 4.8.2

⏯ Playground Link

Playground - long cause copy some angular types for perfect reproduction - actual code on the end of code

💻 Code

export const serializeParams = <T extends {}>(query: T): HttpParams => {
  return new HttpParams().appendAll(
        Object.fromEntries(Object.entries(query))
        )
};


export const serializeParams2 = <T extends {}>(query: T): HttpParams => {
      return new HttpParams().appendAll(
        Object.fromEntries(Object.entries(query).filter(val => val[1] !== undefined))
    )
};


export const serializeParams3 = <T extends {}>(query: T): HttpParams => {
  return new HttpParams().appendAll(Object.fromEntries(Object.entries(query)
    .filter(([_, value]) => value !== undefined)
    .map(([key, value]) => {
      if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
        return [key, JSON.stringify(value)];
      } else {
        return [key, value ?? ''];
      }
    })));
};


export const serializeParams4 = <T extends {}>(query: T): HttpParams => {
  const entries = Object.entries(query)
    .filter(([_, value]) => value !== undefined)
    .map(([key, value]) => {
      if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
        return [key, JSON.stringify(value)];
      } else {
        return [key, value ?? ''];
      }
    });

  return new HttpParams().appendAll(Object.fromEntries(entries)); // here very weird - moving body to separate const fixes type error in VS code but build still fails with error
};

🙁 Actual behavior

unfiltered and filtered arrays behave differently

🙂 Expected behavior

unfiltered and filtered arrays behave the same

[jcalz]

🔎 Search Terms

This should probably be replaced with a list of terms people can search for to find this issue and related issues.

[graphemecluster]

@MartinJohns Yes, I can confirm that. All the versions I tried raise the same error. I didn’t agree with the OP either. (I am just a passer-by.)