Code To:
SlimLoadingBarService.start(()=>{alert("complete!")});
When I run the code ,it start ok but can't get my completed status like the "complete!";
I check your slim-loading-bar.service.js code on ng2-slim-loading-bar@4.0.0.
it does not has the function to onComplete ,
then i fix it simple and the code is down:

SlimLoadingBarService.prototype.start = function (onCompleted) {
var _this = this;
if (onCompleted === void 0) {
onCompleted = null;
}else
this.onCompleted=onCompleted;
// Stop current timer
this.stop();
// Make it visible for sure
this.visible = true;
// Run the timer with milliseconds iterval
this._intervalCounterId = setInterval(function () {
// Increment the progress and update view component
_this.progress++;
// If the progress is 100% - call complete
if (_this.progress === 100) {
_this.complete();
}
}, this.interval);
};
SlimLoadingBarService.prototype.complete = function () {
var _this = this;
this.progress = 100;
this.stop();
setTimeout(function () {
// Hide it away
_this.visible = false;
setTimeout(function () {
// Drop to 0
_this.progress = 0;
}, 250);
}, 250);
this.onCompleted();
};
SlimLoadingBarService.prototype.onCompleted = function () {
};

thanks for your giving!