如何将此 foreach 推送循环变成减速器 function？

Question

I currently have a function that looks like this:

export const getTags = (element: Record<string, any>) => {
  const tags: Record<string, any> = {};
  Object.keys(element).forEach((key: string) => {
    if (element[key] === true) {
      tags[key] = true;
    } else if (element[key] === false) {
      tags[key] = false;
    }
  });
  return tags;
};

You call it like this:

const objToCheck = {
  foo: true,
  bar: false,
  baz: true,
  moo: [],
  boo: "hello",
}

const tags = getTags(objToCheck);
// returns: { foo: true, bar: false, baz: true }

I currently do this with quite an inefficient way by making an empty object and pushing to it, I was wondering if there was a different method like reduce to fill this object properly? Making the code a bit more clean.

The purpose of my function is to extract all values with booleans to a new object with the same key names and values.

Answer 1

good solution should look something like this:

export const getTags = (element: Record<string, any>) => {
  return Object.fromEntries(
    Object.entries(element)
      .filter(([key,val]) => val instanceof Boolean)
  );
};

we just filter out nonboolean values

Answer 2

You can do it like this:

 const objToCheck = { foo: true, bar: false, baz: true, moo: [], boo: "hello", } const result = Object.entries(objToCheck).reduce((acc, [key, value])=> { if([true, false].includes(value)) acc[key]=value; return acc; },{}) console.log('Result: ', result)

Answer 3

Try this

export const getTags = (element: Record < string, any > ) => Object.entries(element).reduce((acc, [key, val]) => {
    if (typeof key === "boolean") {
        acc[key] = val;
    }
    return acc;
}, {});

Answer 4

To modify the original object

const getTags = obj => {
    for(const key in obj) {
        if(typeof (obj[key]) !== 'boolean' ) delete obj[key]
    }
    return obj
}

To return a copy

const getTags = ({...obj}) => {
    for(const key in obj) {
        if(typeof (obj[key]) !== 'boolean' ) delete obj[key]
    }
    return obj
}