Only

Only

Return whitelisted properties of an object.

Only will only return the properties of an object that we are intrested in.

A simple and an effective module from Tj Holowaychuk .

Install it: npm install only

Sample usage:

Say we have a response from a mongo query which looks like:

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var obj = {
  name: 'tobi',
  last: 'holowaychuk',
  email: 'tobi@learnboost.com',
  _id: '12345'
};

Out of which we are intrested on only name and email, so all we need to do is:

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let only = require('only');

var obj = {
  name: 'tobi',
  last: 'holowaychuk',
  email: 'tobi@learnboost.com',
  _id: '12345'
};

console.log(only(obj,'name email'));

// ^ Would log { name: 'tobi', email: 'tobi@learnboost.com' }

console.log(only(obj,'name foo bar baz'));

// Smart enough to omit undefineds and logs { name: 'tobi' }

The cool part being, the entire module is just ten lines and it reads:

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module.exports = function(obj, keys){
  obj = obj || {};
  if ('string' == typeof keys) keys = keys.split(/ +/);
  return keys.reduce(function(ret, key){
      if (null == obj[key]) return ret;
      ret[key] = obj[key];
      return ret;
  }, {});
};

GIF FTW!

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