New Super Ultimate Injector Box Art
Suyay Escarsega
I have a set of angular2 components that should all get some service injected. My first thought was that it would be best to create a super class and inject the service there. Any of my components would then extend that superclass but this approach does not work.
Every injectable class has to declare the dependencies as constructor parameters and if the superclass also has dependencies these need to be listed in the subclass' constructor as well and passed along to the superclass with the super(dep1, dep2) call.
It hides dependencies which makes code harder to read.
It violates expectations of one familiar with how Angular2 DI works.
It breaks offline compilation that generates static code to replace declarative and imperative DI to improve performance and reduce code size.
Instead of injecting all the services manually I created a class providing the services, e.g., it gets the services injected. This class is then injected into the derived classes and passed on to the base class.
Your concern is entirely related to components inheritance. Most likely, the reason you landed on this question is because of the overwhelming amount of non-dry (WET?) code you need to repeat in each derived class. If you want to benefits of a single entry point for all your components and services, you will need to do the extra step.
There is also a disadvantage if you decide use the constructor of a derived class, as you will need to call super() and pass in all the dependencies. Although I don't really see a use case that necessitates the use of constructor instead of ngOnInit, it is entirely possible that such a use case exists.
From what I understand in order to inherit from base class you first need to instantiate it. In order to instantiate it you need to pass its constructor required parameters thus you pass them from child to parent thru a super() call so it makes sense. Injector of course is another viable solution.
Some time ago some of my client wants to join two BIG angular projects to yesterday (angular v4 into angular v8). Project v4 uses BaseView class for each component and it contains tr(key) method for translations (in v8 I use ng-translate). So to avoid switching translations system and edit hundreds of templates (in v4) or setup 2 translation system in parallel I use following ugly hack (I'm not proud of it) - in AppModule class I add following constructor:
STP Super Concentrated Fuel Injector Cleaner is a DIY fuel injector cleaner that contains concentrated detergents that help dissolve and remove harmful carbon, gum, and varnish deposits on fuel injectors. Without cleaning, deposits can lead to hard starts, lost acceleration and rough idling. Our Super Concentrated Fuel Injector Cleaner is made with jet fuel, a high-quality carrier of active ingredients.
From the look of it, the "PoE injector" is a passive "run power along network connection" type adapter. It most probably uses the otherwise unused wires in a Fast Ethernet connection to pass the PSU power to the device. This isn't PoE.
You can tell by looking at the "injector's" power supply: if it outputs 48 to 54 V it most probably is a real PoE injector and should work with any PoE device. If the PSU just outputs 9 or 12 V it's a passive adapter which you'd have to replace.
Specially blended formula to help prevent build-up ofperformance-reducing deposits such as dirt, gum, and varnish from fuelinjectors and carburetors. Also aids in removing water from gas tank. Usedregularly, it can smooth rough idle and ease hard starting, fight power lossand reduce exhaust emissions, and protect against fuel system rust andcorrosion.
For years contractors have been asking for more chemical induction performance. Most injectors will provide up to 10-12% through the injector. Super Suds Sucker injectors provide up to 3 times that much but quite often this is not enough to satisfy the needs of the contractor who is up against a real tough job. To answer this call we have re-valved and balanced a popular ShurFlo pump that will answer the call. When you install this 12-V pump between the Chemical Supply and Injector and your injector will draw as much as 3 times the normal performance rate.
Downstream injectors operate using the venturi principle. This principle states that when water flows through a restricted area, its velocity increases and its pressure decreases. So a chemical injector has a restrictive orifice that the water stream is forced through. It also has a small port that chemical is drawn into because of the vacuum created. The vacuum is only created when there is little back pressure being exerted on the injector outlet port. So when the pressure washer is operated with a high-pressure nozzle, no chemical is drawn into the water stream. Operating with low pressure at the nozzle reduces pressure on the outlet port, and the suction draws the chemical into the water stream. A check valve keeps water from entering the chemical while the machine is operating at high pressure.
Downstream chemical injectors have a valve that keeps the water from entering the chemical pick up tube. It is a simple combination, starting from the injector body, of a spring, ball and o-ring. The ball and spring are housed inside a nipple or adjustment knob and nipple. The pressure of the water when the equipment is operated at high pressure overcomes the spring resistance and seals the ball against the o-ring. This prevents water from entering the chemical tubing. When the pressure is reduced at the outlet of the injector, the spring pushes the ball away from the o-ring seat and chemical path is cleared. The ball in this assembly can be made of steel, stainless steel, or ceramic. A ceramic ball is recommended if the injector is used with acids or caustics.
A downstream chemical injector reacts to the back pressure exerted on its outlet port. Aside from hose length, the biggest factor affecting the back pressure produced is the actual pressure nozzle where the water flow finally emerges. When the equipment is operating with a high-pressure nozzle with a hole small enough to maintain a pressure of approximately 800 PSI or greater on the injector outlet, no chemical can enter the water stream. When a chemical or soap nozzle is used, and the pressure is reduced below this point, the ball can lift from the seat inside the injector, and allow chemical to flow. The lower the pressure, the easier it is for the chemical to enter the water stream. The larger the hole size on the chemical nozzle, the lower the pressure becomes. Common chemical nozzle hole sizes are 30, 40, and 50. The higher the water flow, the larger the hole needs to be to continue to operate at a pressure low enough for the chemical to be introduced into the water stream.
The chemical injector relies on the venturi nozzle to create a high pressure, fast stream of water inside the injector body. This nozzle must be properly sized to create the venturi action. The proper sized venturi nozzle will reduce the flow of water leaving the injector slightly, while allowing chemical to be injected. Installing a smaller venturi nozzle can help with chemical draw, but it also reduces water flow. One of the reasons chemical injectors wear out is that the venturi nozzle wears larger due to the water and chemical action. As the nozzle wears, the percentage of chemical drawn slowly lowers. This happens so slowly that the pressure wash operator may not notice it until the wash job becomes unacceptable, or difficult to accomplish.
The higher the chemical viscosity, or thicker the chemical is, the lower the draw rate of the injector will be. The chemical viscosity will increase if chemical is stored in open containers and evaporation occurs. Some thick chemicals need to be thinned prior to use to allow injection. Injection works best with chemical products that have a viscosity that is close to that of water.
There are many operational limitations that have to be considered to understand the function of the downstream injector in the field. To be successful working with a downstream injector it is important that you understand these operational factors.
The best place to install the injector is typically at the outlet of the pressure washer just prior to the high-pressure hose. If the equipment has a ball valve that allows the water to be turned off without shutting off the machine, be sure to install the injector after the ball valve to enable injector replacement without shutting off the equipment. Always install quick disconnects on the injector for quick change out. Always have a spare ready to replace the injector being used. Have quick connects, chemical tubing, and a filter already installed on the spare to reduce any potential down time. Most injectors have an arrow that indicates the direction the water flow should travel as it goes through the injector. Installing a chemical injector facing the wrong direction will definitely reduce its effectiveness.
STP Super Concentrated Fuel Injector Cleaner is a fuel injector cleaner that you can do yourself that contains concentrated detergents that will help dissolve and remove harmful carbon, gum, and varnish deposits on fuel injectors. If you didn't clean out fuel injectors, deposits can lead to hard starts on your vehicle, lost acceleration and even rough idling. The Super Concentrated Fuel Injector Cleaner is made with jet fuel, a high-quality carrier of active ingredients.
Unlike some software emulated PoE, this PoE injector adopts hardware IEEE802.3af/at/bt PoE chipset and compatible to both Mode A and Mode B PD device. It follows PD Detection -> Classisication Type -> Power On procedures to prevent stanard PD device from damaging.
The ID2600-XDS benefits from Dual Slope Matching, a method of matching the flow rate in both the linear, and nonlinear operating range, providing better cylinder to cylinder consistency at low pulse widths.
With the progression of turbo technology, and increased use of alcohol fuels, greater demands are placed on fuel injectors, and they are often required to deliver fuel well outside of their linear operating range.
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