Source code of released version | Source code of development version
This package improves ECMAScript 5 compliance in all browers, particularly older browsers, and especially Internet Explorer 8 (and earlier).
Like the ecmascript package, es5-shim is installed by default for all new apps. Though it technically can be removed, the expectation is that it will only be removed if the app author wishes to install an equivalent package instead (e.g. something based on core-js), or wishes to drop support for older browsers altogether.
Given these assumptions, as of Meteor 1.2, packages may safely begin to rely on ES5 features that are patched or polyfilled by es5-shim. Packages are discouraged from depending directly on es5-shim, however, as that would make it considerably more difficult for app authors to remove or replace the package.