Add basic position to dropup/right/left

[ysds]

Fixes: #25304

This changes fix a position of dropright/left menu on navbar. And give a basic position for dropup/right/left for disable popper support in the future enhancement (#24092).

Note:

• The direction of carets on navbar is not responsive. (e.g. a caret of dropright is turning to the right even on mobile.)
• display is not defined for dropright. In many cases it should be use in/on an inline element (.btn-group or .d-inline-block etc). Otherwise the dropright menu will jump to the right end (left: 100%) of the div.

[Johann-S]

is it possible to see a live example in a CodePen ?

[ysds]

While creating a demo, I noticed a bug in this PR. The dropleft/dropup menu is broken by right, bottom property when not disabled popper (actually by default).

Demo: https://codepen.io/anon/pen/MrqGBV

[ysds]

Closing since has a bug

[Johann-S]

Dropup works pretty well currently (with Popper.js disabled) : https://getbootstrap.com/docs/4.0/examples/navbar-bottom/

[Johann-S]

I think it's doable to fix that issue @ysds , bottom: 100% should be applied only for Dropdown and not for Dropup

[ysds]

Dropup works pretty well currently (with Popper.js disabled) :

Yes. because it has the spesific scss:

bootstrap/scss/_navbar.scss

Lines 193 to 197 in 1f490ec

	.dropup {
	.dropdown-menu {
	top: auto;
	bottom: 100%;
	}

but dropup will not work the outside of navbar after the future enhancement (#24092).