|  | 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/compiler/js_lib/preambles/d8.js <output>.js | 
|  |  | 
|  | - jsshell: | 
|  | jsshell -f <sdk>/lib/_internal/compiler/js_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. |