jobbet litt med higher order functions

eloquentjavascript/05_higher_order_functions/summarizing_with_reduce.js

@@ -2,19 +2,88 @@ const SCRIPTS = require("./scripts.js");
 
 function reduce(array, combine, start) {
     let current = start;
-    for(let element of array){
+    for (let element of array) {
         current = combine(current, element);
     }
     return current
 }
-console.log(reduce([1,2,3,4], (a,b) => a +b, 0));
-console.log([1,2,3,4].reduce((a,b) => a +b));
+console.log(reduce([1, 2, 3, 4], (a, b) => a + b, 0));
+console.log([1, 2, 3, 4].reduce((a, b) => a + b));
 
 function characterCount(script) {
     return script.ranges.reduce((count, [from, to]) => {
         return count + (to - from);
     }, 0);
 }
-console.log(SCRIPTS.reduce((a,b) => {
-    return characterCount(a) < characterCount(b) ? b : a;
-}));
+// console.log(SCRIPTS.reduce((a, b) => {
+//     return characterCount(a) < characterCount(b) ? b : a;
+// }));
+// let biggest = null;
+
+// for (let script of SCRIPTS) {
+//     if (biggest == null ||
+//         characterCount(biggest) < characterCount(script)) {
+//         biggest = script;
+//     }
+// }
+// console.log(biggest);
+
+function average(array){
+    return array.reduce((a,b) => a + b) / array.length;
+} 
+// console.log(Math.round(average(SCRIPTS.filter(s => !s.living).map(s => s.year))));
+
+let total = 0, count = 0;
+for (let script of SCRIPTS){
+    if(script.living) {
+        total += script.year;
+        count += 1;
+    }
+}
+// console.log(Math.round(total / count));
+
+function characterScript(code){
+    for (let script of SCRIPTS) {
+        if (script.ranges.some(([from, to]) => {
+            return code >= from && code < to;
+        })) {
+            return script
+        }
+    }
+    return null;
+}
+console.log(characterScript(1200));
+let roseDragon = "🌹🐉";
+for (let char of roseDragon){
+    console.log(char);
+}
+
+function countBy(items, groupName){
+    let counts = [];
+    for (let item of items){
+        let name = groupName(item);
+        let known = counts.find(c => c.name == name);
+        if (!known) {
+            counts.push({name, count: 1});
+        } else {
+            known.count++;
+        }
+    }
+    return counts;
+}
+// console.log(countBy([1,2,3,4,5], n => n > 2));
+
+function textScripts(text){
+    let scripts = countBy(text, char => {
+        let script = characterScript(char.codePointAt(0));
+        return script ? script.name : "none";
+    }).filter(({name}) => name != "none");
+
+    let total = scripts.reduce((n, {count}) => n + count, 0);
+    if (total == 0){return "No scripts found!"};
+
+    return scripts.map(({name, count}) => {
+        return `${Math.round(count * 100 / total)}% ${name}`;
+    }).join(", ");
+}
+console.log(textScripts('英国的狗说"woof", 俄罗斯的狗说"тяв"'));