Destructuring In Lambda Function Returns Unexpected Value

Correct, expected value returned when function used with destructuring: [{'k':'key1','v':'val1'},{'k':'key2','v':'val2'},{'k':'key3','v':'val3'}] However, when lambda function is

Solution 1:

You could use destructuring inside of the parameters of the callback of Array#map

let array = [{ k: 'key1', v: 'val1', z: 'z1' }, { k: 'key2', v: 'val2', z: 'z2' }, { k: 'key3', v: 'val3', z: 'z3' }];

console.log(array.map(({ k, v }) => ({ k, v })));

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Solution 2:

This is caused beceause this code

{k, v} = x; 

is not actually returning {k, v} but x. So you need to destruct object instead first of returning destructive assigment.

Solution 3:

The expression ({k, v} = x) assigns to the globalk and v variables, and returns the right hand side value x. So you've essentially got an identity function x => x.

You should use destructuring in the parameters, and build an object literal as the return value:

[…].map( ({k, v}) => ({k, v}) );

Solution 4:

This works for me:

console.log(JSON.stringify([{
  k: 'key1',
  v: 'val1',
  z: 'z1'
}, {
  k: 'key2',
  v: 'val2',
  z: 'z2'
}, {
  k: 'key3',
  v: 'val3',
  z: 'z3'
}].map(x => {
  let { k, v } = x;
  return { k, v };
})));