[jQuery] about "speed up references to window"
I see "var window = this" from latest svn code
I use firebug debugger it.
info:"Exception: redeclaration of const window"
but in core.js
var
// Will speed up references to window, and allows munging its name.
window = this,
// Will speed up references to undefined, and allows munging its
name.
undefined,
// Map over jQuery in case of overwrite
_jQuery = window.jQuery,
// Map over the $ in case of overwrite
_$ = window.$,
i want to know what does "speed up references to window" mean?