1 files changed, 105 insertions, 0 deletions
diff --git a/code/app/src/utilities/dom-helpers.ts b/code/app/src/utilities/dom-helpers.ts
new file mode 100644
index 0000000..94a74c1
--- /dev/null
+++ b/code/app/src/utilities/dom-helpers.ts
@@ -0,0 +1,105 @@
+interface CreateElementOptions {
+    name: string,
+    properties?: object,
+    children?: Array<HTMLElement | Function | Node>
+}
+
+export function create_element_from_object(elementOptions: CreateElementOptions): HTMLElement {
+    return create_element(elementOptions.name, elementOptions.properties, elementOptions.children);
+}
+
+export function create_element(name: string, properties?: object, children?: Array<HTMLElement | any>): HTMLElement {
+    if (!name || name.length < 1) {
+        throw new Error("name is required");
+    }
+    const node = document.createElement(name);
+    if (properties) {
+        for (const [key, value] of Object.entries(properties)) {
+            // @ts-ignore
+            node[key] = value;
+        }
+    }
+
+    if (children && children.length > 0) {
+        let actualChildren = children;
+        if (typeof children === "function") {
+            // @ts-ignore
+            actualChildren = children();
+        }
+        for (const child of actualChildren) {
+            node.appendChild(child as Node);
+        }
+    }
+    return node;
+}
+
+// https://stackoverflow.com/a/45215694/11961742
+export function get_selected_options(domElement: HTMLSelectElement): Array<string> {
+    const ret = [];
+
+    // fast but not universally supported
+    if (domElement.selectedOptions !== undefined) {
+        for (let i = 0; i < domElement.selectedOptions.length; i++) {
+            ret.push(domElement.selectedOptions[i].value);
+        }
+
+        // compatible, but can be painfully slow
+    } else {
+        for (let i = 0; i < domElement.options.length; i++) {
+            if (domElement.options[i].selected) {
+                ret.push(domElement.options[i].value);
+            }
+        }
+    }
+    return ret;
+}
+
+
+export function get_element_position(element: HTMLElement | any) {
+    if (!element) return {x: 0, y: 0};
+    let x = 0;
+    let y = 0;
+    while (true) {
+        x += element.offsetLeft;
+        y += element.offsetTop;
+        if (element.offsetParent === null) {
+            break;
+        }
+        element = element.offsetParent;
+    }
+    return {x, y};
+}
+
+export function restrict_input_to_numbers(element: HTMLElement, specials: Array<string> = [], mergeSpecialsWithDefaults: boolean = false): void {
+    if (!element) return;
+    element.addEventListener("keydown", (e) => {
+        const defaultSpecials = ["Backspace", "ArrowLeft", "ArrowRight", "Tab"];
+        let keys = specials.length > 0 ? specials : defaultSpecials;
+        if (mergeSpecialsWithDefaults && specials) {
+            keys = [...specials, ...defaultSpecials];
+        }
+        if (keys.indexOf(e.key) !== -1) {
+            return;
+        }
+        if (isNaN(parseInt(e.key))) {
+            e.preventDefault();
+        }
+    });
+}
+
+export function element_has_focus(element: HTMLElement): boolean {
+    return element === document.activeElement;
+}
+
+export function move_focus(element: HTMLElement): void {
+    if (!element) {
+        element = document.getElementsByTagName("body")[0];
+    }
+    element.focus();
+    // @ts-ignore
+    if (!element_has_focus(element)) {
+        element.setAttribute("tabindex", "-1");
+        element.focus();
+    }
+}
+