JS对象循环返回未定义，而Lodash映射返回值

Question

I have a loop in JS, and once the loop is complete the value is returning as null, if I use lodash for the same purpose, it returns the result.

This is what I tried:

JS:

const jsRows = Object.entries(response).forEach(([key, row]) => {
    return row;
});
console.log(jsRows) ==> Output undefined

Lodash:

const loRows = map(response, row => {
    return row;
});
console.log(loRows) ==> Output Array

Answer 1

The .forEach() function always returns undefined . It is not at all the same thing as a .map() function. The native JavaScript Array.prototype.map() also returns a new array.

The .forEach() function is for "doing something" with each element of an array in a situation where you don't need a new result comprised of a transformation of each array value. The .map() function, on the other hand, is for transforming an array into a new array based on a transformation of each array element.