From 53fca4f3408fd4b1d7e8167b08e9061abef5ccaa Mon Sep 17 00:00:00 2001
From: Samuel Lorch <sam@soontm.de>
Date: Tue, 11 Apr 2023 19:43:09 +0200
Subject: [PATCH] Feat custom multiselect (#12)

* WIP Multiselect

* Reworked Multiselect into multiple Components
- Also finished feature implementation

---------

Co-authored-by: adroslice <adriel.m.slice@gmail.com>
---
 .../src/components/inputs/DropdownInput.vue   | 208 ++++++++++++++++++
 client/src/components/inputs/MultiSelect.vue  |  38 ++++
 client/src/components/inputs/SingleSelect.vue |  38 ++++
 client/src/global-styles/components.css       |   8 +-
 client/src/global-styles/transitions.css      |   7 +
 client/src/pages/index.vue                    |   3 +-
 client/src/util.ts                            |  16 ++
 7 files changed, 315 insertions(+), 3 deletions(-)
 create mode 100644 client/src/components/inputs/DropdownInput.vue
 create mode 100644 client/src/components/inputs/MultiSelect.vue
 create mode 100644 client/src/components/inputs/SingleSelect.vue
 create mode 100644 client/src/util.ts

diff --git a/client/src/components/inputs/DropdownInput.vue b/client/src/components/inputs/DropdownInput.vue
new file mode 100644
index 0000000..36b5972
--- /dev/null
+++ b/client/src/components/inputs/DropdownInput.vue
@@ -0,0 +1,208 @@
+<!-- Base component that implements selecting single and multiple values from a list in a type-unsafe manner -->
+<script lang="ts">
+export type Index = string | number | symbol;
+</script>
+
+<script setup lang="ts">
+import { equals, isNullish } from '../../util';
+// --- Prop setup ---
+const props = withDefaults(defineProps<{
+  // Two-Way Bindings (v-model)
+  modelValue?: any,
+  search?: string,
+
+  // One-Way Bindings
+  multiple?: boolean,
+  options?: Record<Index, {
+    [key: Index]: any, // Allow additional properties for customization
+    display?: string,
+  }>,
+}>(), {
+  modelValue: null,
+  search: "",
+  multiple: false,
+  options: () => ({}),
+});
+let { multiple, options } = $(props);
+
+const emit = defineEmits<{
+  (e: 'update:modelValue', value: any): void,
+  (e: 'update:search', value: string): void,
+}>();
+
+// Hook up two-way bindings
+let modelValue = $ref(multiple ? props.modelValue ?? [] : props.modelValue);
+watch(() => props.modelValue, (val: any) => { if (!equals(val, modelValue)) modelValue = val; }, { deep: true });
+watch($$(modelValue), (val: any) => { if(!equals(val, props.modelValue)) emit('update:modelValue', modelValue); }, { deep: true });
+let search = $ref(props.search);
+watch(() => props.search, (val: string) => { if (!equals(val, search)) search = val; }, { deep: true });
+watch($$(search), (val) => { if(!equals(val, props.search)) emit('update:search', search); }, { deep: true });
+
+// --- Everything Else  ---
+let expanded = $ref(false);
+let navigated = $ref(0);
+let inputDiv: HTMLElement | null = $ref(null);
+let input: HTMLElement | null = $ref(null);
+let valueButton: HTMLElement | null = $ref(null);
+
+const selCount = $computed(() => modelValue?.length || 0);
+
+watch($$(multiple), () => modelValue = multiple ? [] : null );
+
+function expand() {
+  expanded = true;
+  navigated = 0;
+  focus();
+}
+
+function focus() {
+  if (multiple || isNullish(modelValue)) input?.focus();
+  else valueButton?.focus();
+}
+
+let skipFocusIn = false;
+function focusIn() {
+  if (skipFocusIn) return skipFocusIn = false;
+  expand();
+}
+
+function toggle(key: any) {
+  if (multiple) {
+    const mv = modelValue as Index[];
+    if (mv?.includes(key)) mv?.splice(mv?.indexOf(key), 1);
+    else mv?.push(key);
+    focus();
+    return;
+  }
+
+  inputDiv?.focus();
+  navigated = 0;
+  if (modelValue === null || modelValue !== key) {
+    modelValue = key;
+    expanded = false;
+  }
+  else modelValue = null;
+  skipFocusIn = true;
+  setTimeout(focus, 0); // nextTick causes double fire on keydown.Enter, so defer to next event loop instance
+}
+
+function handleKeydown(e: KeyboardEvent) {
+  switch (e.key) {
+  case "Backspace":
+  case "Delete":
+    if (!modelValue || search !== "" || !multiple) break;
+    if (navigated === 0) modelValue.pop();
+    else if (navigated > 0) navigated = 0;
+    else {
+      modelValue.splice(navigated, 1);
+      navigated = 0;
+    }
+    modelValue = modelValue;
+    break;
+  case "ArrowUp":
+    navigated--;
+    if (-navigated > selCount) navigated = 0;
+    e.preventDefault(); // Prevent cursor from moving to the front/back
+    break;
+  case "ArrowDown":
+    navigated++;
+    if (navigated > Object.entries(options).length) navigated = 0;
+    e.preventDefault(); // Prevent cursor from moving to the front/back
+    break;
+  case "Enter":
+    if (!expanded) expand();
+    else if (navigated > 0) {
+      toggle(Object.entries(options)[navigated-1][0]);
+    }
+    break;
+  case "Escape":
+    if (navigated !== 0) navigated = 0;
+    else expanded = false;
+    break;
+  default: break;
+  }
+}
+</script>
+<template>
+  <div :class="{'multiselect': 1, 'cl-secondary': 1, expanded}" ref="inputDiv"
+       @keydown="handleKeydown"
+       @focusin="$event => { if (!inputDiv?.contains($event.relatedTarget as HTMLElement)) focusIn(); }"
+       @focusout="$event => expanded = inputDiv?.contains($event.relatedTarget as HTMLElement) ?? false">
+    <div class="head">
+      <div class="selection" v-if="multiple" tabindex="-1">
+        <div v-for="(key, index) of modelValue as Index[]" :key="key" v-text="options[key].display" :class="{navigated: selCount + navigated === index}"
+             @click="() => toggle(key)"/>
+      </div>
+      <div class="searchbar">
+        <div class="expand button" :tabindex="expanded ? undefined : -1">
+          <i-material-symbols-expand-circle-down-outline width="1em" height="1em"/>
+        </div>
+        <input v-if="multiple || modelValue === null" placeholder="Search..." v-model="search" ref="input"/>
+        <button v-else v-text="options[modelValue]?.display" ref="valueButton"
+                @click="() => toggle(modelValue)"/>
+      </div>
+    </div>
+    <Transition name="fade-fast">
+      <div tabindex="-1" class="dropdown" v-if="expanded">
+        <div v-for="([key, option], index) in Object.entries(options)" :key="key" :class="{selected: modelValue?.includes(key), navigated: navigated === index + 1}"
+             @click="() => toggle(key)">
+          <template v-if="multiple">
+            <i-material-symbols-check-box-outline v-if="modelValue?.includes(key)" width="1em" height="1em"/>
+            <i-material-symbols-check-box-outline-blank v-else width="1em" height="1em"/>
+          </template>
+          <div v-text="option.display"/>
+        </div>
+      </div>
+    </Transition>
+  </div>
+</template>
+<style scoped>
+* { border: none; }
+.selection, .searchbar, .dropdown {
+  border: 1px solid var(--cl-fg);
+}
+.selection { border-bottom: none; }
+.dropdown {
+  border-top: none;
+  overflow-y: auto;
+  max-height: 10rem;
+}
+
+.selection, .dropdown {
+  flex-grow: 1;
+  padding: 0.5rem;
+  gap: 0.5rem;
+  background-color: var(--cl-bg);
+}
+
+.selection > div {
+  background-color: var(--cl-bg-el);
+}
+
+:is(.selection, .dropdown) > div {
+  flex-flow: row nowrap;
+  padding: 0.25rem;
+  gap: 0.5rem;
+  cursor: pointer;
+}
+:is(.selection, .dropdown) > div > div {
+  justify-content: center;
+}
+:is(.selection, .dropdown) > div.selected {
+  background-color: var(--cl-bg-sl);
+}
+:is(.selection, .dropdown) > div:hover,
+:is(.selection, .dropdown) > div.navigated {
+  background-color: var(--cl-bg-hl);
+}
+
+.searchbar { flex-flow: row nowrap; background: var(--cl-bg-hl) }
+.expand { padding: 0px; }
+.searchbar > :not(:first-child) { flex-grow: 1; justify-content: flex-start; }
+input { padding: 0.25rem; outline: none; }
+.expand > svg { transition: all 0.2s ease-out; }
+.expanded .expand > svg { transform: rotate(180deg); }
+
+div:empty { display: none; }
+button { padding: 0.25rem; }
+</style>
\ No newline at end of file
diff --git a/client/src/components/inputs/MultiSelect.vue b/client/src/components/inputs/MultiSelect.vue
new file mode 100644
index 0000000..a7f6327
--- /dev/null
+++ b/client/src/components/inputs/MultiSelect.vue
@@ -0,0 +1,38 @@
+<!-- Wrapper component that sets "multiple" on DropdownInput to true and declares its type to be an array of any -->
+<script setup lang="ts">
+import { Index } from "./DropdownInput.vue";
+import { equals } from "../../util";
+const props = withDefaults(defineProps<{
+  // Two-Way Bindings (v-model)
+  modelValue?: Index[],
+  search?: string,
+
+  // One-Way Bindings
+  options?: Record<Index, {
+    [key: Index]: any, // Allow additional properties for customization
+    display?: string,
+  }>,
+}>(), {
+  modelValue: () => [],
+  search: "",
+  options: () => ({}),
+});
+
+const emit = defineEmits<{
+  (e: 'update:modelValue', value: any): void,
+  (e: 'update:search', value: string): void,
+}>();
+
+// Hook up two-way bindings
+let modelValue = $ref([]);
+watch(() => props.modelValue, (val: any) => { if (!equals(val, modelValue)) modelValue = val; }, { deep: true });
+watch($$(modelValue), (val: any) => { if(!equals(val, props.modelValue)) emit('update:modelValue', modelValue); }, { deep: true });
+let search = $ref(props.search);
+watch(() => props.search, (val: string) => { if (!equals(val, search)) search = val; }, { deep: true });
+watch($$(search), (val) => { if(!equals(val, props.search)) emit('update:search', search); }, { deep: true });
+
+let { options } = $(props);
+</script>
+<template>
+  <DropdownInput :multiple="true" :options="options" v-model="modelValue"/>
+</template>
diff --git a/client/src/components/inputs/SingleSelect.vue b/client/src/components/inputs/SingleSelect.vue
new file mode 100644
index 0000000..74b375f
--- /dev/null
+++ b/client/src/components/inputs/SingleSelect.vue
@@ -0,0 +1,38 @@
+<!-- Wrapper component that sets "multiple" on DropdownInput to false and declares its type to be an Index -->
+<script setup lang="ts">
+import { Index } from "./DropdownInput.vue";
+import { equals } from "../../util";
+const props = withDefaults(defineProps<{
+  // Two-Way Bindings (v-model)
+  modelValue?: Index | null,
+  search?: string,
+
+  // One-Way Bindings
+  options?: Record<Index, {
+    [key: Index]: any, // Allow additional properties for customization
+    display?: string,
+  }>,
+}>(), {
+  modelValue: null,
+  search: "",
+  options: () => ({}),
+});
+
+const emit = defineEmits<{
+  (e: 'update:modelValue', value: any): void,
+  (e: 'update:search', value: string): void,
+}>();
+
+// Hook up two-way bindings
+let modelValue: Index[] | null = $ref(null);
+watch(() => props.modelValue, (val: any) => { if (!equals(val, modelValue)) modelValue = val; }, { deep: true });
+watch($$(modelValue), (val: any) => { if(!equals(val, props.modelValue)) emit('update:modelValue', modelValue); }, { deep: true });
+let search = $ref(props.search);
+watch(() => props.search, (val: string) => { if (!equals(val, search)) search = val; }, { deep: true });
+watch($$(search), (val) => { if(!equals(val, props.search)) emit('update:search', search); }, { deep: true });
+
+let { options } = $(props);
+</script>
+<template>
+  <DropdownInput :multiple="false" :options="options" v-model="modelValue"/>
+</template>
diff --git a/client/src/global-styles/components.css b/client/src/global-styles/components.css
index 1ba83ee..a67580b 100644
--- a/client/src/global-styles/components.css
+++ b/client/src/global-styles/components.css
@@ -20,6 +20,11 @@ button, .button {
   min-height: 1.5rem;
 }
 
+input {
+  height: 1.5rem;
+  padding: 0.25rem;
+}
+
 form {
   display: grid;
   grid-template-columns: auto 1fr;
@@ -67,7 +72,8 @@ button, .button {
 .nav-body .button {
   background-color: var(--cl-bg);
 }
-.button:hover, button:hover {
+.button:hover, button:hover,
+.button:focus, button:focus {
   background-color: var(--cl-bg-hl);
 }
 
diff --git a/client/src/global-styles/transitions.css b/client/src/global-styles/transitions.css
index 87dc1bc..dc53338 100644
--- a/client/src/global-styles/transitions.css
+++ b/client/src/global-styles/transitions.css
@@ -3,4 +3,11 @@
 }
 .fade-enter-from, .fade-leave-to {
   opacity: 0;
+}
+
+.fade-fast-enter-active, .fade-fast-leave-active { 
+  transition: all 0.1s ease-out !important;
+}
+.fade-fast-enter-from, .fade-fast-leave-to {
+  opacity: 0;
 }
\ No newline at end of file
diff --git a/client/src/pages/index.vue b/client/src/pages/index.vue
index 429f8f4..2bc6b18 100644
--- a/client/src/pages/index.vue
+++ b/client/src/pages/index.vue
@@ -23,7 +23,7 @@ onMounted(async() => {
 </script>
 
 <template>
-  <div>
+  <div style="overflow-y: auto;">
     <PageHeader title="Dashboard">
     </PageHeader>
     <div v-if="!loading" v-for="(link, index) in links" :key="index">
@@ -32,7 +32,6 @@ onMounted(async() => {
     <div v-else>
       Loading...
     </div>
-
   </div>
 </template>
 
diff --git a/client/src/util.ts b/client/src/util.ts
new file mode 100644
index 0000000..2d8b29e
--- /dev/null
+++ b/client/src/util.ts
@@ -0,0 +1,16 @@
+// Performs a type-agnostic deep comparison of two values by process of elimination. This mainly covers the use cases of Primitives, Objects and Arrays, but not certain builtins like Dates.
+export function equals(a: any, b: any): boolean {
+  if (typeof a !== typeof b) return false;   // Different types can't be equal, except number and bigint but who cares. Null and undefined are considered different.
+  if (typeof a !== 'object') return a === b; // A simple comparison suffices for non-objects
+  if (isNullish(a) !== isNullish(b)) return false; // A common use case is checking for something to exist vs. not, so it's covered explicitly here
+  if (isNullish(a) && isNullish(b)) return true;
+  if (a instanceof Array && !(b instanceof Array)) return false; // Could be generalized with Object.getPrototypeOf, but I think it's preferable to have "pure" and regular objects match (Look up Object.create(null))
+  if (a?.length !== b?.length)  return false; // Another not technically necessary but common point of comparison.
+  for (const key of new Set(Object.keys(a).concat(Object.keys(b)))) // All there's left is to deep-compare what are clearly objects. The keys of both need to be merged to prevent an extra key on one side being ignored.
+    if (!equals(a[key],  b[key])) return false;
+  return true; // Only once all points of inequality are rules out can we say for certain that the two values are equal.
+}
+
+export function isNullish(value: any) {
+  return !!(value === null || value === undefined);
+}
\ No newline at end of file