Improve sort order of Select component filtered results

src/components/Select.js

@@ -1,11 +1,9 @@
-import React, { useMemo } from 'react';
+import React, { useMemo, useState } from 'react';
 import ReactSelect from 'react-select';
 import cn from 'classnames';
 
 import * as css from './Select.module.css';
 
-const toOption = (value) => ({ value, label: value });
-
 export const Select = ({
   title,
   options,
@@ -17,8 +15,12 @@ export const Select = ({
   variant,
   instanceId
 }) => {
+  const [input, setInput] = useState('');
   const opts = useMemo(() => options.map(toOption), [options]);
-  const handleOnChange = (o, action) => onChange(o ? o.value : o);
+  const filteredOpts = useMemo(
+    () => (input === '' ? opts : filterAndSortRank(opts, input)),
+    [opts, input]
+  );
 
   return (
     <section className={cn(css.root, className, { [css[variant]]: variant })}>
@@ -36,10 +38,12 @@ export const Select = ({
             placeholder={placeholder}
             className={css.select}
             classNamePrefix="rs"
-            options={opts}
-            defaultValue={selected ? toOption(selected) : selected}
-            onChange={handleOnChange}
+            options={filteredOpts}
+            defaultValue={selected ? toOption(selected) : ''}
+            onChange={(o) => onChange(o ? o.value : null)}
             instanceId={instanceId}
+            onInputChange={setInput}
+            filterOption={() => true}
           />
 
           <div className={css.itemSpacer}></div>
@@ -48,4 +52,49 @@ export const Select = ({
     </section>
   );
 };
+
 export default Select;
+
+const toOption = (value) => ({ value, label: value });
+
+// trim, lowercase and strip accents
+const normalize = (value) =>
+  value
+    .trim()
+    .toLowerCase()
+    .normalize('NFD')
+    .replace(/[\u0300-\u036f]/g, '');
+
+const rank = (value, input) => {
+  // exact match: highest priority
+  if (value === input) return 0;
+
+  // complete word match: higher priority based on word position
+  const words = value.split(' ');
+  for (let i = 0; i < words.length; i++) {
+    if (words[i] === input) return i + 1;
+  }
+
+  // partial match: lower priority based on character position
+  const index = value.indexOf(input);
+  return index === -1 ? Number.MAX_SAFE_INTEGER : 1000 + index;
+};
+
+const filterAndSortRank = (options, input) => {
+  // It doesn't seem possible to only sort the filtered options in react-select, but we can re-implement the filtering to do so.
+  // https://github.com/JedWatson/react-select/discussions/4426
+
+  const normalizedInput = normalize(input);
+
+  return options
+    .filter((o) => normalize(o.value).includes(normalizedInput))
+    .sort((optA, optB) => {
+      const rankDelta =
+        rank(normalize(optA.value), normalizedInput) -
+        rank(normalize(optB.value), normalizedInput);
+
+      if (rankDelta !== 0) return rankDelta;
+
+      return optA.value.localeCompare(optB.value);
+    });
+};