Revisions to Check if a value is an object in JavaScript

Formatting. The link to the updated version of underscore.js linked to the master branch, which could misalign the line anchors in the URL in future versions

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edited Jan 15, 2020 at 14:21

Gust van de Wal

5.3k
1
27
52

The official underscore.js uses this checkprovides the following method to find out if something is really an object:

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

The updated underscore.js library is now using the following, becauseBecause of a previous bug in V8 and minor micro speed optimization., the method looks as follows since underscore.js 1.7.0 (August 2014):

// Is a given variable an object?
_.isObject = function(obj) {
  var type = typeof obj;
  return type === 'function' || type === 'object' && !!obj;
};

The official underscore.js uses this check to find out if something is really an object

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

The updated underscore.js library is now using the following, because of a previous bug in V8 and minor micro speed optimization.

// Is a given variable an object?
_.isObject = function(obj) {
  var type = typeof obj;
  return type === 'function' || type === 'object' && !!obj;
};

underscore.js provides the following method to find out if something is really an object:

_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

Because of a previous bug in V8 and minor micro speed optimization, the method looks as follows since underscore.js 1.7.0 (August 2014):

_.isObject = function(obj) {
  var type = typeof obj;
  return type === 'function' || type === 'object' && !!obj;
};

quote the lines of code precisely, instead of own version

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edited Mar 7, 2019 at 11:52

Daan

8k
5
47
54

The official underscore.js uses this check to find out if something is really an object

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

The updated underscore.js library is now using the following, because of a previous bug in V8 and minor micro speed optimization.

// Is a given variable an object?
_.isObject = function(obj) {
  returnvar type = typeof objobj;
  return type === 'function' || (typeof objtype === 'object' && !!obj);obj;
};

The official underscore.js uses this check to find out if something is really an object

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

The updated underscore.js library is now using the following, because of a previous bug in V8 and minor micro speed optimization.

// Is a given variable an object?
_.isObject = function(obj) {
  return typeof obj === 'function' || (typeof obj === 'object' && !!obj);
};

The official underscore.js uses this check to find out if something is really an object

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

The updated underscore.js library is now using the following, because of a previous bug in V8 and minor micro speed optimization.

// Is a given variable an object?
_.isObject = function(obj) {
  var type = typeof obj;
  return type === 'function' || type === 'object' && !!obj;
};

updated link + added updated way in underscore.js to determine object

Source Link

edited Feb 21, 2019 at 12:25

Daan

8k
5
47
54

The official underscore.js underscore.js uses this check to find out if something is really an object

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

The updated underscore.js library is now using the following, because of a previous bug in V8 and minor micro speed optimization.

// Is a given variable an object?
_.isObject = function(obj) {
  return typeof obj === 'function' || (typeof obj === 'object' && !!obj);
};

The official underscore.js uses this check to find out if something is really an object

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

The official underscore.js uses this check to find out if something is really an object

// Is a given variable an object?
_.isObject = function(obj) {
  return obj === Object(obj);
};

UPDATE

The updated underscore.js library is now using the following, because of a previous bug in V8 and minor micro speed optimization.

// Is a given variable an object?
_.isObject = function(obj) {
  return typeof obj === 'function' || (typeof obj === 'object' && !!obj);
};

Bounty Awarded with 100 reputation awarded by Oriol

occurred Sep 4, 2016 at 20:21

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answered Feb 5, 2013 at 11:50

Daan

8k
5
47
54

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