core/util.js
function functionBind(f, obj) {
  if (NATIVE_FUNCTION_BIND) {
    return NATIVE_FUNCTION_BIND.call(f, obj);
  }

  return function boundFunction_() {
    return f.apply(obj, arguments);
  };
}
function functionBind(f, obj) {
  if (NATIVE_FUNCTION_BIND) {
    return NATIVE_FUNCTION_BIND.call(f, obj);
  }

  return function boundFunction_() {
    return f.apply(obj, arguments);
  };
}
function functionBind ( f , obj ) { if ( NATIVE_FUNCTION_BIND ) { return NATIVE_FUNCTION_BIND . call ( f , obj ) ; } return function boundFunction_ ( ) { return f . apply ( obj , arguments ) ; } ; }
Bind a function's 'this' value.
@param {function} f The function.
@param {object} obj The object.
@return {function} The bound function.
Bind a function s this value .