es5-shim

es5-shim.js and es5-shim.min.js monkey-patch a JavaScript context to
contain all EcmaScript 5 methods that can be faithfully emulated with a
legacy JavaScript engine.
Note: As es5-shim.js is designed to patch the native Javascript
engine, it should be the library that is loaded first.

es5-sham.js and es5-sham.min.js monkey-patch other ES5 methods as
closely as possible. For these methods, as closely as possible to ES5
is not very close. Many of these shams are intended only to allow code
to be written to ES5 without causing run-time errors in older engines.
In many cases, this means that these shams cause many ES5 methods to
silently fail. Decide carefully whether this is what you want.
Note: es5-sham.js requires es5-shim.js to be able to work properly.

Tests

The tests are written with the Jasmine BDD test framework.
To run the tests, navigate to <root-folder>/tests/ , or,
simply npm install and npm test.

Shims

Complete tests

• Array.prototype.every
• Array.prototype.filter
• Array.prototype.forEach
• Array.prototype.indexOf
• Array.prototype.lastIndexOf
• Array.prototype.map
• Array.prototype.slice
• Array.prototype.some
• Array.prototype.sort
• Array.prototype.reduce
• Array.prototype.reduceRight
• Array.prototype.push
• Array.prototype.join
• Array.isArray
• Date.now
• Date.prototype.toJSON
• Function.prototype.bind
  • :warning: Caveat: the bound function has a prototype property.
  • :warning: Caveat: bound functions do not try too hard to keep you
    from manipulating their arguments and caller properties.
  • :warning: Caveat: bound functions don't have checks in call and
    apply to avoid executing as a constructor.
• Number.prototype.toFixed
• Number.prototype.toPrecision
• Object.keys
• String.prototype.split
• String.prototype.trim
• String.prototype.lastIndexOf
• String.prototype.replace
  • Firefox (through v29) natively handles capturing groups incorrectly.
• Date.parse (for ISO parsing)
• Date.prototype.toISOString
• parseInt
• parseFloat
• Error.prototype.toString
• Error.prototype.name
• Error.prototype.message
• RegExp.prototype.toString

Shams

• :warning: Object.create

  For the case of simply "begetting" an object that inherits
  prototypically from another, this should work fine across legacy
  engines.

  :warning: The second argument is passed to Object.defineProperties
  which will probably fail either silently or with extreme prejudice.

• :warning: Object.getPrototypeOf

  This will return "undefined" in some cases. It uses __proto__ if
  it's available. Failing that, it uses constructor.prototype, which
  depends on the constructor property of the object's prototype having
  not been replaced. If your object was created like this, it won't
  work:

    function Foo() {
    }
    Foo.prototype = {};
  

  Because the prototype reassignment destroys the constructor
  property.

  This will work for all objects that were created using
  Object.create implemented with this library.

• :warning: Object.getOwnPropertyNames

  This method uses Object.keys, so it will not be accurate on legacy
  engines.

• Object.isSealed

  Returns "false" in all legacy engines for all objects, which is
  conveniently guaranteed to be accurate.

• Object.isFrozen

  Returns "false" in all legacy engines for all objects, which is
  conveniently guaranteed to be accurate.

• Object.isExtensible

  Works like a charm, by trying very hard to extend the object then
  redacting the extension.

May fail

• :warning: Object.getOwnPropertyDescriptor

  The behavior of this shim does not conform to ES5. It should
  probably not be used at this time, until its behavior has been
  reviewed and been confirmed to be useful in legacy engines.

• :warning: Object.defineProperty

  In the worst of circumstances, IE 8 provides a version of this
  method that only works on DOM objects. This sham will not be
  installed. The given version of defineProperty will throw an
  exception if used on non-DOM objects.

  In slightly better circumstances, this method will silently fail to
  set "writable", "enumerable", and "configurable" properties.

  Providing a getter or setter with "get" or "set" on a descriptor
  will silently fail on engines that lack "defineGetter" and
  "defineSetter", which include all versions of IE.

  https://github.com/es-shims/es5-shim/issues#issue/5

• :warning: Object.defineProperties

  This uses the Object.defineProperty shim.

• Object.seal

  Silently fails on all legacy engines. This should be
  fine unless you are depending on the safety and security
  provisions of this method, which you cannot possibly
  obtain in legacy engines.

• Object.freeze

  Silently fails on all legacy engines. This should be
  fine unless you are depending on the safety and security
  provisions of this method, which you cannot possibly
  obtain in legacy engines.

• Object.preventExtensions

  Silently fails on all legacy engines. This should be
  fine unless you are depending on the safety and security
  provisions of this method, which you cannot possibly
  obtain in legacy engines.

Example of applying ES compatability shims in a browser project

<script src="https://cdnjs.cloudflare.com/ajax/libs/es5-shim/4.5.7/es5-shim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/es5-shim/4.5.7/es5-sham.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/json3/3.3.2/json3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/es6-shim/0.34.2/es6-shim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/es6-shim/0.34.2/es6-sham.min.js"></script>
<script src="https://wzrd.in/standalone/es7-shim@latest"></script>
<script src="other-libs.js"></script>