feat: functions n closures tasks completed

art-sh · Dec 12, 2020 · 127bd08 · 127bd08
1 parent 0c24f5d
commit 127bd08
Showing 1 changed file with 65 additions and 16 deletions.
diff --git a/src/09-functions-n-closures-tasks.js b/src/09-functions-n-closures-tasks.js
@@ -23,8 +23,8 @@
  *   getComposition(Math.sin, Math.asin)(x) => Math.sin(Math.asin(x))
  *
  */
-function getComposition(/* f, g */) {
-  throw new Error('Not implemented');
+function getComposition(f, g) {
+  return (x) => f(g(x));
 }
 
 
@@ -44,8 +44,8 @@ function getComposition(/* f, g */) {
  *   power05(16) => 4
  *
  */
-function getPowerFunction(/* exponent */) {
-  throw new Error('Not implemented');
+function getPowerFunction(exponent) {
+  return (number) => number ** exponent;
 }
 
 
@@ -62,8 +62,12 @@ function getPowerFunction(/* exponent */) {
  *   getPolynom(8)     => y = 8
  *   getPolynom()      => null
  */
-function getPolynom() {
-  throw new Error('Not implemented');
+function getPolynom(...args) {
+  return (x) => args.reduce((out, number, i) => {
+    const pow = (args.length - 1) - i;
+
+    return out + (number * (x ** pow));
+  }, 0);
 }
 
 
@@ -81,8 +85,15 @@ function getPolynom() {
  *   ...
  *   memoizer() => the same random number  (next run, returns the previous cached result)
  */
-function memoize(/* func */) {
-  throw new Error('Not implemented');
+function memoize(func) {
+  const funcStored = func;
+  let result;
+
+  return (...args) => {
+    if (result === undefined) result = funcStored(...args);
+
+    return result;
+  };
 }
 
 
@@ -101,8 +112,22 @@ function memoize(/* func */) {
  * }, 2);
  * retryer() => 2
  */
-function retry(/* func, attempts */) {
-  throw new Error('Not implemented');
+function retry(func, attempts) {
+  let count = attempts;
+
+  return () => {
+    while (count) {
+      count -= 1;
+
+      try {
+        return func();
+      } catch (e) {
+        //
+      }
+    }
+
+    return undefined;
+  };
 }
 
 
@@ -129,8 +154,16 @@ function retry(/* func, attempts */) {
  * cos(3.141592653589793) ends
  *
  */
-function logger(/* func, logFunc */) {
-  throw new Error('Not implemented');
+function logger(func, logFunc) {
+  return (...args) => {
+    const argsCollection = args.map((arg) => JSON.stringify(arg)).join(',');
+
+    logFunc(`${func.name}(${argsCollection}) starts`);
+    const result = func(...args);
+    logFunc(`${func.name}(${argsCollection}) ends`);
+
+    return result;
+  };
 }
 
 
@@ -147,8 +180,17 @@ function logger(/* func, logFunc */) {
  *   partialUsingArguments(fn, 'a','b','c')('d') => 'abcd'
  *   partialUsingArguments(fn, 'a','b','c','d')() => 'abcd'
  */
-function partialUsingArguments(/* fn, ...args1 */) {
-  throw new Error('Not implemented');
+function partialUsingArguments(fn, ...args) {
+  const argsStorage = [...args];
+
+  const out = (...argsClosure) => {
+    out.valueOf = () => fn(...argsStorage);
+    argsStorage.push(...argsClosure);
+
+    return out;
+  };
+
+  return out;
 }
 
 
@@ -169,8 +211,15 @@ function partialUsingArguments(/* fn, ...args1 */) {
  *   getId4() => 7
  *   getId10() => 11
  */
-function getIdGeneratorFunction(/* startFrom */) {
-  throw new Error('Not implemented');
+function getIdGeneratorFunction(startFrom) {
+  let id = startFrom;
+
+  return () => {
+    const result = id;
+    id += 1;
+
+    return result;
+  };
 }