feat: o-tooltip opts.target can be HTMLElement

Fixes #1609.

components/o-tooltip/src/js/tooltip.js

@@ -31,7 +31,7 @@ class Tooltip {
 
 		Tooltip._tooltips.set(this.tooltipEl, this);
 
-		this.targetNode = document.getElementById(this.opts.target);
+		this.targetNode = typeof this.opts.target === 'string' ? document.getElementById(this.opts.target) : this.opts.target;
 		this.target = new Tooltip.Target(this.targetNode);
 		this.tooltipPosition = this._getConfiguredTooltipPosition();
 		this.tooltipAlignment = null;
@@ -123,6 +123,10 @@ class Tooltip {
 			Tooltip.throwError("tooltip.target is not set. An target for the tooltip to point at must be provided");
 		}
 
+		if (!typeof opts.target === 'string' || !opts.target instanceof HTMLElement) {
+			Tooltip.throwError("tooltip.target is invalid, it must be either an ID selector string or HTMLElement");
+		}
+
 		// Check that the value of tooltip position is valid. Default to below.
 		if (opts.position) {
 			if (Tooltip.validTooltipPositions.indexOf(opts.position) === -1) {

components/o-tooltip/test/Tooltip.test.js

@@ -254,6 +254,12 @@ describe("Tooltip", () => {
 			const opts = Tooltip.checkOptions({"target": "#el"});
 			proclaim.isObject(opts);
 		});
+
+		it("does not error if HTMLElement is passed as opts.target", () => {
+			const targetEl = document.createElement('div');
+			Tooltip.checkOptions({target: targetEl});
+			proclaim.isFalse(throwStub.called);
+		})
 	});
 
 	describe('constructElement', () => {