Implementation
callConstructor(Function constr, List arguments) {
if (arguments == null) {
return JS('Object', 'new #()', constr);
}
if (JS('bool', '# instanceof Array', arguments)) {
int argumentCount = JS('int', '#.length', arguments);
switch (argumentCount) {
case 0:
return JS('Object', 'new #()', constr);
case 1:
var arg0 = JS('', '#[0]', arguments);
return JS('Object', 'new #(#)', constr, arg0);
case 2:
var arg0 = JS('', '#[0]', arguments);
var arg1 = JS('', '#[1]', arguments);
return JS('Object', 'new #(#, #)', constr, arg0, arg1);
case 3:
var arg0 = JS('', '#[0]', arguments);
var arg1 = JS('', '#[1]', arguments);
var arg2 = JS('', '#[2]', arguments);
return JS('Object', 'new #(#, #, #)', constr, arg0, arg1, arg2);
case 4:
var arg0 = JS('', '#[0]', arguments);
var arg1 = JS('', '#[1]', arguments);
var arg2 = JS('', '#[2]', arguments);
var arg3 = JS('', '#[3]', arguments);
return JS(
'Object', 'new #(#, #, #, #)', constr, arg0, arg1, arg2, arg3);
}
}
// The following code solves the problem of invoking a JavaScript
// constructor with an unknown number arguments.
// First bind the constructor to the argument list using bind.apply().
// The first argument to bind() is the binding of 't', so add 'null' to
// the arguments list passed to apply().
// After that, use the JavaScript 'new' operator which overrides any binding
// of 'this' with the new instance.
var args = <dynamic>[null]..addAll(arguments);
var factoryFunction = JS('', '#.bind.apply(#, #)', constr, constr, args);
// Without this line, calling factoryFunction as a constructor throws
JS('String', 'String(#)', factoryFunction);
// This could return an UnknownJavaScriptObject, or a native
// object for which there is an interceptor
return JS('Object', 'new #()', factoryFunction);
// TODO(sra): Investigate:
//
// var jsObj = JS('', 'Object.create(#.prototype)', constr);
// JS('', '#.apply(#, #)', constr, jsObj,
// []..addAll(arguments.map(_convertToJS)));
// return _wrapToDart(jsObj);
}