[working] add grid filter

lib/utility.js

@@ -27,10 +27,30 @@ function throttle(method, delay = 100, context = g, ...args) {
     }
 }
 
+function debounce(method, delay = 100, context = g, ...args) {
+    if (method == null) {
+        return;
+    }
+    method.tiid && clearTimeout(method.tiid);
+    method.tiid = setTimeout(() => method.apply(context, args), delay);
+}
+
 function truncate(v) {
     return (v > 0 ? Math.floor : Math.ceil)(v);
 }
 
+function distinct(array, key, filter) {
+    const dict = Object.create(null);
+    for (let item of array) {
+        const v = typeof filter === 'function' ? filter(item) : item[key];
+        const val = v?.value ?? v;
+        if (!Object.prototype.hasOwnProperty.call(dict, val)) {
+            dict[val] = v;
+        }
+    }
+    return Object.values(dict);
+}
+
 function isEmail(text) {
     return /^\w[-\w.+]*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/.test(text);
 }
@@ -65,7 +85,9 @@ export {
     isMobile,
     // functions
     throttle,
+    debounce,
     truncate,
+    distinct,
     isEmail,
     isPhone
 }