Perf nit in spdlogService.ts

[jrieken]

re #39572

In SpdLogService you could save a few arrays and iterations by not declaring var-args but by using the the gold old arguments-objects. In pretty TS we have this trace(message: string, ...args: any[]):void which, thanks to ES5, thanks to IE11, will be downlevel compiled to

SpdLogService.prototype.trace = function (message) {
            var args = [];
            for (var _i = 1; _i < arguments.length; _i++) {
                args[_i - 1] = arguments[_i];
            }

Every time one of the log methods is being called (1) a new array is being allocated and (2) the arguments are iterated once. Changing the TypeScript to trace():void will still compile. You would simply pass the arguments object to the format-method. Like so

trace(): void {
	if (this.level <= LogLevel.Trace) {
		this.logger.trace(this.format(arguments));
	}
}

//..
private format(args:IArguments): string {
  //...
}

[jrieken]

Oh, and the format function itself can save two arrays and one array-iteration by just incrementally building the string it returns