The files in this directory polyfill some of the functionality that browsers
provide. When running command-line JS evaluators it is frequently necessary to
execute the preambles before executing the output of dart2js.

=Usage=
- d8:
    d8 <sdk>/lib/_internal/js_runtime/lib/preambles/d8.js <output>.js

- jsshell:
    jsshell -f <sdk>/lib/_internal/js_runtime/lib/preambles/d8.js -f <output>.js

- node.js:
  The d8 preamble file works for most programs.

  Unfortunately we are not aware of any easy way to provide multiple input files
  to node. It seems to be necessary to concatenate the d8 preamble and the
  dart2js output.