feat(slider): make changeAmount multiplier configurable when using meta/ctrl/alt with left/right arrow keys

[androidfreakers]

Actual Behavior:

• Slider is changing values 4 times when using with combination of ctrl/alt key.
• It should change values based on step count.

Angular Versions: *

• Angular: 1.5.8
• Angular material 1.1.1

[androidfreakers]

I have checked source code for this:

function keydownListener(ev) {
      if (isDisabled()) return;

      var changeAmount;
      if (vertical ? ev.keyCode === $mdConstant.KEY_CODE.DOWN_ARROW : ev.keyCode === $mdConstant.KEY_CODE.LEFT_ARROW) {
        changeAmount = -step;
      } else if (vertical ? ev.keyCode === $mdConstant.KEY_CODE.UP_ARROW : ev.keyCode === $mdConstant.KEY_CODE.RIGHT_ARROW) {
        changeAmount = step;
      }
      changeAmount = invert ? -changeAmount : changeAmount;
      if (changeAmount) {
        if (ev.metaKey || ev.ctrlKey || ev.altKey) {
          changeAmount *= 4;
        }
        ev.preventDefault();
        ev.stopPropagation();
        scope.$evalAsync(function() {
          setModelValue(ngModelCtrl.$viewValue + changeAmount);
        });
      }
    }

It is clear that is was intensional to give such hidden feature. No one knows about the because documentation does not say anything about that.

How can we make this configurable?

[Splaktar]

https://github.com/angular/material/pull/11210 addresses the missing documentation for the Meta, Control, or Alt key behavior.

Leaving this issue open to indicate that we would be open to a PR from the community that allows the multiplier to be configurable (currently hard coded to 4 steps I.e. 4 * step).

[Splaktar]

This was also mentioned in PR https://github.com/angular/material/pull/11517. Modifiers still do 4 * step and now page up/down do 10 * step.

It would be easy for the community to submit a PR to make the step size multipliers configurable.