Simple lodash.get function in javascript

lodash.get.js

/* Implementation of lodash.get function */
function getProp( object, keys, defaultVal ){
  keys = Array.isArray( keys )? keys : keys.split('.');
  object = object[keys[0]];
  if( object && keys.length>1 ){
    return getProp( object, keys.slice(1) );
  }
  return object === undefined? defaultVal : object;
}

/* Implementation of lodash.set function */
function setProp( object, keys, val ){
  keys = Array.isArray( keys )? keys : keys.split('.');
  if( keys.length>1 ){
    object[keys[0]] = object[keys[0]] || {};
    return setProp( object[keys[0]], keys.slice(1), val );
  }
  object[keys[0]] = val;
}

The above version doesn't support some formats supported by lodash.get.

Like: get(obj, ['forecast', 0, 'main.temp'], null)

But this version do it:

function get (object, path, value) {
  const pathArray = Array.isArray(path) ? path : path.split('.').filter(key => key)
  const pathArrayFlat = pathArray.flatMap(part => typeof part === 'string' ? part.split('.') : part)

  return pathArrayFlat.reduce((obj, key) => obj && obj[key], object) || value
}

The above version don't support some formats supported by lodash.get.

Like: get(obj, ['forecast', 0, 'main.temp'], null)

But this version do it:

function get (object, path, value) {
  const pathArray = Array.isArray(path) ? path : path.split('.').filter(key => key)
  const pathArrayFlat = pathArray.flatMap(part => typeof part === 'string' ? part.split('.') : part)

  return pathArrayFlat.reduce((obj, key) => obj && obj[key], object) || value
}

If return value is falsy it will not play properly.

function get (object, path, value) {
  const pathArray = Array.isArray(path) ? path : path.split('.').filter(key => key);
  const pathArrayFlat = pathArray.flatMap(part => typeof part === 'string' ? part.split('.') : part);
  const checkValue = pathArrayFlat.reduce((obj, key) => obj && obj[key], object);
  return  checkValue === undefined ? value : checkValue
}

Sorry @Sooro1024, but I don't think it's necessary!
Did you notice the || in my return?

return pathArrayFlat.reduce((obj, key) => obj && obj[key], object) || value

If the reduce result is falsy (undefined inclusive), the value is returned.

So, if the expected return is a number, just pass a value = 0. And if a boolean is expected, just pass a value = false.

So, I think extra code is not necessary. Just take some Node or DevTools console test:

And here is a use test:

I used this in react, in a table component and for me, it was necessary that if the value is falsy show the provided default value. That is the reason I prefer to check with `===` for me, it is a more safe and common solution. But I am very grateful to you. For this function

…

On Wed, Jan 22, 2020 at 10:16 PM Alex Bruno Cáceres < ***@***.***> wrote: Sorry @Sooro1024 <https://github.com/Sooro1024>, but I don't think it's necessary! Did you notice the || in my return? return pathArrayFlat.reduce((obj, key) => obj && obj[key], object) || value If the reduce result is falsy (undefined inclusive), the value is returned. So, if the expected return is a number, just pass a value = 0. And if a boolean is expected, just pass a value = false. So, I think extra code is not necessary. Just take some Node or DevTools console test: [image: js] <https://user-images.githubusercontent.com/2638399/72920615-8d3d6100-3d41-11ea-8f00-efeac20d9938.png> And here is a use test: [image: get] <https://user-images.githubusercontent.com/2638399/72921345-0093a280-3d43-11ea-85f1-99707ed51241.png> — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <https://gist.github.com/d0ee530e6ee75bad6fd30c98e5ad9dab?email_source=notifications&email_token=ALJC4N5LING2JDBVFLQPRJ3Q7CEO5A5CNFSM4H4PA6VKYY3PNVWWK3TUL52HS4DFVNDWS43UINXW23LFNZ2KUY3PNVWWK3TUL5UWJTQAGAHG6#gistcomment-3149423>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ALJC4N6OXV5X2USYZCL7AXDQ7CEO5ANCNFSM4H4PA6VA> .

@pi0, you solution throws an error, but thanks for inspiration for the most performant solution from provided here.

const getPropByPath = (object, path, defaultValue) => {
    const _path = Array.isArray(path)
        ? path
        : path.split('.');
    if (object && _path.length) return getPropByPath(object[_path.shift()], _path, defaultValue);
    return object === undefined ? defaultValue : object;
};

// without default value
const getPropByPath = (object, path) => {
    const _path = Array.isArray(path)
        ? path
        : path.split('.');
    if (object && _path.length) return getPropByPath(object[_path.shift()], _path);
    return object;
};

Benchmarks: https://jsbench.me/ogkwc7fxlg/1. I didn't include implementations out of scope of original lodash.get and those which iterate over whole path without break - i.e. reduce-based - they're too slow.

@pi0, you solution throws an error, but thanks for inspiration for the most performant solution from provided here.

const getPropByPath = (object, path, defaultValue) => {
    const _path = Array.isArray(path)
        ? path
        : path.split('.');
    if (object && _path.length) return getPropByPath(object[_path.shift()], _path, defaultValue);
    return object === undefined ? defaultValue : object;
};

// without default value
const getPropByPath = (object, path) => {
    const _path = Array.isArray(path)
        ? path
        : path.split('.');
    if (object && _path.length) return getPropByPath(object[_path.shift()], _path);
    return object;
};

Benchmarks: https://jsbench.me/ogkwc7fxlg/1. I didn't include implementations out of scope of original lodash.get and those which iterate over whole path without break - i.e. reduce-based - they're too slow.

This solution fixed for me a problem: Empty string counts as undefined.
I'd like the empty string back. It's not the same (for me).

I'm talking about the version without default value.

setProp is not work.

I created a fork of this version that includes tests, handles falsey values (including undefined), and handles objects-inside-arrays (i.e. '[0].id') as well as arrays-inside-objects (i.e. 'a.b[0].c'):

https://gist.github.com/andrewchilds/30a7fb18981d413260c7a36428ed13da

many thanks