diff --git a/README.md b/README.md
index c0c70a9..8de6fd1 100644
--- a/README.md
+++ b/README.md
@@ -33,29 +33,28 @@ Calculate  average and scoring based on Wilson Score Equation
 
 ### Node.js:
 
-Sync v14, ECMAScript modules [have became the official standard format](https://nodejs.org/docs/latest-v14.x/api/esm.html#esm_modules_ecmascript_modules).
-
-Just [enable](https://nodejs.org/api/packages.html#determining-module-system) and enjoy with ES6 import/export syntax.
-
-
 ```js
 import {
   score,
   rate,
   average
 } from 'average-rating'
-```
 
-For regular CommonJS environment, `require` can be used as below:
+// with CommonJS environment
+// const { score, rate, average } = require('feed-reader/dist/cjs/average-rating.js')
 
-```js
-const {
-  score,
-  rate,
-  average
-} = require('average-rating/cjs/average-rating.js')
+score(80, 20) // => 0.71
+average([134055, 57472, 143135, 365957, 1448459]) // => 4.4
+rate([134055, 57472, 143135, 365957, 1448459]) // => 0.84
 ```
 
+
+##### Note:
+
+> Since Node.js v14, ECMAScript modules [have became the official standard format](https://nodejs.org/docs/latest-v14.x/api/esm.html#esm_modules_ecmascript_modules).
+> Just ensure that you are [using module system](https://nodejs.org/api/packages.html#determining-module-system) and enjoy with ES6 import/export syntax.
+
+
 ### Browsers:
 
 Currently ECMAScript modules work fine on almost browsers:
diff --git a/build.js b/build.js
index b33a26c..0ab71bc 100644
--- a/build.js
+++ b/build.js
@@ -14,17 +14,7 @@ execSync('rm -rf dist')
 execSync('mkdir dist')
 
 const buildTime = (new Date()).toISOString()
-const longComment = [
-  '/**',
-  ` * ${pkg.name}@${pkg.version}`,
-  ` * built with esbuild at: ${buildTime}`,
-  ` * repository: ${pkg.repository.url}`,
-  ` * maintainer: ${pkg.author}`,
-  ` * License: ${pkg.license}`,
-  '**/'
-].join('\n')
-
-const shortComment = [
+const comment = [
   `// ${pkg.name}@${pkg.version}, by ${pkg.author}`,
   `built with esbuild at ${buildTime}`,
   `published under ${pkg.license} license`
@@ -35,7 +25,7 @@ const baseOpt = {
   bundle: true,
   charset: 'utf8',
   target: ['es2020', 'node14'],
-  minify: true,
+  minify: false,
   write: true
 }
 
@@ -46,7 +36,7 @@ const esmVersion = {
   mainFields: ['module'],
   outfile: 'dist/average-rating.esm.js',
   banner: {
-    js: longComment
+    js: comment
   }
 }
 buildSync(esmVersion)
@@ -58,7 +48,7 @@ const cjsVersion = {
   mainFields: ['main'],
   outfile: 'dist/cjs/average-rating.js',
   banner: {
-    js: longComment
+    js: comment
   }
 }
 buildSync(cjsVersion)
@@ -82,8 +72,9 @@ const iifeVersion = {
   target: ['es2020'],
   globalName: 'AverageRating',
   outfile: 'dist/average-rating.min.js',
+  minify: true,
   banner: {
-    js: shortComment
+    js: comment
   }
 }
 buildSync(iifeVersion)
diff --git a/build.test.js b/build.test.js
new file mode 100644
index 0000000..0cc5f90
--- /dev/null
+++ b/build.test.js
@@ -0,0 +1,41 @@
+// release.test
+
+/* eslint-env jest */
+
+import {
+  existsSync,
+  readFileSync
+} from 'fs'
+
+const pkg = JSON.parse(readFileSync('./package.json'))
+
+const esmFile = `${pkg.name}.esm.js`
+const cjsFile = `cjs/${pkg.name}.js`
+const minFile = `${pkg.name}.min.js`
+
+const runtest = (fname) => {
+  const fpath = `./dist/${fname}`
+  describe(`Validate ${fname} version output`, () => {
+    test(`Check if ${fpath} file created`, () => {
+      expect(existsSync(fpath)).toBeTruthy()
+    })
+    const constent = readFileSync(fpath, 'utf8')
+    const lines = constent.split('\n')
+    test('Check if file meta contains package info', () => {
+      expect(lines[0].includes(`${pkg.name}@${pkg.version}`)).toBeTruthy()
+      expect(lines[0].includes(pkg.author)).toBeTruthy()
+      expect(lines[0].includes(pkg.license)).toBeTruthy()
+    })
+  })
+  return fpath
+}
+
+const arr = [
+  esmFile,
+  cjsFile,
+  minFile
+]
+
+arr.forEach((fname) => {
+  runtest(fname)
+})
diff --git a/dist/average-rating.esm.js b/dist/average-rating.esm.js
index a02a9e7..d591bf4 100644
--- a/dist/average-rating.esm.js
+++ b/dist/average-rating.esm.js
@@ -1,8 +1,43 @@
-/**
- * average-rating@2.0.0
- * built with esbuild at: 2022-01-03T14:48:10.361Z
- * repository: https://github.com/ndaidong/average-rating
- * maintainer: @ndaidong
- * License: MIT
-**/
-var n=(t,e)=>{if(t===0&&e===0)return 0;let o=((t+1.9208)/(t+e)-1.96*Math.sqrt(t*e/(t+e)+.9604)/(t+e))/(1+3.8416/(t+e));return Number(o.toFixed(2))},x=t=>{let e=t.length,o=t[0],c=t[e-1],u=(1/(e-1)).toFixed(2),s=e-1;for(let r=1;r<s;r++){let l=(u*r).toFixed(2);c+=t[r]*l,o+=t[s-r]*l}return n(c,o)},d=t=>{let e=t.reduce((s,r)=>s+r,0);if(e===0)return 0;let o=0,c=1;t.forEach(s=>{o+=s*c,c++});let u=o/e;return Number(u.toFixed(1))};export{d as average,x as rate,n as score};
+// average-rating@2.0.1, by @ndaidong - built with esbuild at 2022-01-04T03:58:54.537Z - published under MIT license
+// src/main.js
+var score = (p, n) => {
+  if (p === 0 && n === 0) {
+    return 0;
+  }
+  const r = ((p + 1.9208) / (p + n) - 1.96 * Math.sqrt(p * n / (p + n) + 0.9604) / (p + n)) / (1 + 3.8416 / (p + n));
+  return Number(r.toFixed(2));
+};
+var rate = (rating) => {
+  const size = rating.length;
+  let n = rating[0];
+  let p = rating[size - 1];
+  const step = (1 / (size - 1)).toFixed(2);
+  const totalStep = size - 1;
+  for (let i = 1; i < totalStep; i++) {
+    const ep = (step * i).toFixed(2);
+    p += rating[i] * ep;
+    n += rating[totalStep - i] * ep;
+  }
+  return score(p, n);
+};
+var average = (rating) => {
+  const total = rating.reduce((prev, current) => {
+    return prev + current;
+  }, 0);
+  if (total === 0) {
+    return 0;
+  }
+  let sum = 0;
+  let k = 1;
+  rating.forEach((item) => {
+    sum += item * k;
+    k++;
+  });
+  const r = sum / total;
+  return Number(r.toFixed(1));
+};
+export {
+  average,
+  rate,
+  score
+};
diff --git a/dist/average-rating.min.js b/dist/average-rating.min.js
index c28f76a..9d7577b 100644
--- a/dist/average-rating.min.js
+++ b/dist/average-rating.min.js
@@ -1,2 +1,2 @@
-// average-rating@2.0.0, by @ndaidong - built with esbuild at 2022-01-03T14:48:10.361Z - published under MIT license
+// average-rating@2.0.1, by @ndaidong - built with esbuild at 2022-01-04T03:58:54.537Z - published under MIT license
 var AverageRating=(()=>{var l=Object.defineProperty;var d=Object.getOwnPropertyDescriptor;var f=Object.getOwnPropertyNames;var F=Object.prototype.hasOwnProperty;var h=t=>l(t,"__esModule",{value:!0});var i=(t,e)=>{for(var o in e)l(t,o,{get:e[o],enumerable:!0})},m=(t,e,o,s)=>{if(e&&typeof e=="object"||typeof e=="function")for(let r of f(e))!F.call(t,r)&&(o||r!=="default")&&l(t,r,{get:()=>e[r],enumerable:!(s=d(e,r))||s.enumerable});return t};var a=(t=>(e,o)=>t&&t.get(e)||(o=m(h({}),e,1),t&&t.set(e,o),o))(typeof WeakMap!="undefined"?new WeakMap:0);var k={};i(k,{average:()=>N,rate:()=>b,score:()=>x});var x=(t,e)=>{if(t===0&&e===0)return 0;let o=((t+1.9208)/(t+e)-1.96*Math.sqrt(t*e/(t+e)+.9604)/(t+e))/(1+3.8416/(t+e));return Number(o.toFixed(2))},b=t=>{let e=t.length,o=t[0],s=t[e-1],r=(1/(e-1)).toFixed(2),u=e-1;for(let c=1;c<u;c++){let n=(r*c).toFixed(2);s+=t[c]*n,o+=t[u-c]*n}return x(s,o)},N=t=>{let e=t.reduce((u,c)=>u+c,0);if(e===0)return 0;let o=0,s=1;t.forEach(u=>{o+=u*s,s++});let r=o/e;return Number(r.toFixed(1))};return a(k);})();
diff --git a/dist/cjs/average-rating.js b/dist/cjs/average-rating.js
index ff007c2..f3f0bc4 100644
--- a/dist/cjs/average-rating.js
+++ b/dist/cjs/average-rating.js
@@ -1,8 +1,74 @@
-/**
- * average-rating@2.0.0
- * built with esbuild at: 2022-01-03T14:48:10.361Z
- * repository: https://github.com/ndaidong/average-rating
- * maintainer: @ndaidong
- * License: MIT
-**/
-var l=Object.defineProperty;var d=Object.getOwnPropertyDescriptor;var f=Object.getOwnPropertyNames;var F=Object.prototype.hasOwnProperty;var h=t=>l(t,"__esModule",{value:!0});var i=(t,e)=>{for(var o in e)l(t,o,{get:e[o],enumerable:!0})},m=(t,e,o,s)=>{if(e&&typeof e=="object"||typeof e=="function")for(let r of f(e))!F.call(t,r)&&(o||r!=="default")&&l(t,r,{get:()=>e[r],enumerable:!(s=d(e,r))||s.enumerable});return t};var a=(t=>(e,o)=>t&&t.get(e)||(o=m(h({}),e,1),t&&t.set(e,o),o))(typeof WeakMap!="undefined"?new WeakMap:0);var k={};i(k,{average:()=>N,rate:()=>b,score:()=>x});var x=(t,e)=>{if(t===0&&e===0)return 0;let o=((t+1.9208)/(t+e)-1.96*Math.sqrt(t*e/(t+e)+.9604)/(t+e))/(1+3.8416/(t+e));return Number(o.toFixed(2))},b=t=>{let e=t.length,o=t[0],s=t[e-1],r=(1/(e-1)).toFixed(2),u=e-1;for(let c=1;c<u;c++){let n=(r*c).toFixed(2);s+=t[c]*n,o+=t[u-c]*n}return x(s,o)},N=t=>{let e=t.reduce((u,c)=>u+c,0);if(e===0)return 0;let o=0,s=1;t.forEach(u=>{o+=u*s,s++});let r=o/e;return Number(r.toFixed(1))};module.exports=a(k);0&&(module.exports={average,rate,score});
+// average-rating@2.0.1, by @ndaidong - built with esbuild at 2022-01-04T03:58:54.537Z - published under MIT license
+var __defProp = Object.defineProperty;
+var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
+var __getOwnPropNames = Object.getOwnPropertyNames;
+var __hasOwnProp = Object.prototype.hasOwnProperty;
+var __markAsModule = (target) => __defProp(target, "__esModule", { value: true });
+var __export = (target, all) => {
+  for (var name in all)
+    __defProp(target, name, { get: all[name], enumerable: true });
+};
+var __reExport = (target, module2, copyDefault, desc) => {
+  if (module2 && typeof module2 === "object" || typeof module2 === "function") {
+    for (let key of __getOwnPropNames(module2))
+      if (!__hasOwnProp.call(target, key) && (copyDefault || key !== "default"))
+        __defProp(target, key, { get: () => module2[key], enumerable: !(desc = __getOwnPropDesc(module2, key)) || desc.enumerable });
+  }
+  return target;
+};
+var __toCommonJS = /* @__PURE__ */ ((cache) => {
+  return (module2, temp) => {
+    return cache && cache.get(module2) || (temp = __reExport(__markAsModule({}), module2, 1), cache && cache.set(module2, temp), temp);
+  };
+})(typeof WeakMap !== "undefined" ? /* @__PURE__ */ new WeakMap() : 0);
+
+// src/main.js
+var main_exports = {};
+__export(main_exports, {
+  average: () => average,
+  rate: () => rate,
+  score: () => score
+});
+var score = (p, n) => {
+  if (p === 0 && n === 0) {
+    return 0;
+  }
+  const r = ((p + 1.9208) / (p + n) - 1.96 * Math.sqrt(p * n / (p + n) + 0.9604) / (p + n)) / (1 + 3.8416 / (p + n));
+  return Number(r.toFixed(2));
+};
+var rate = (rating) => {
+  const size = rating.length;
+  let n = rating[0];
+  let p = rating[size - 1];
+  const step = (1 / (size - 1)).toFixed(2);
+  const totalStep = size - 1;
+  for (let i = 1; i < totalStep; i++) {
+    const ep = (step * i).toFixed(2);
+    p += rating[i] * ep;
+    n += rating[totalStep - i] * ep;
+  }
+  return score(p, n);
+};
+var average = (rating) => {
+  const total = rating.reduce((prev, current) => {
+    return prev + current;
+  }, 0);
+  if (total === 0) {
+    return 0;
+  }
+  let sum = 0;
+  let k = 1;
+  rating.forEach((item) => {
+    sum += item * k;
+    k++;
+  });
+  const r = sum / total;
+  return Number(r.toFixed(1));
+};
+module.exports = __toCommonJS(main_exports);
+// Annotate the CommonJS export names for ESM import in node:
+0 && (module.exports = {
+  average,
+  rate,
+  score
+});
diff --git a/dist/cjs/package.json b/dist/cjs/package.json
index 756b2db..83bc0e2 100644
--- a/dist/cjs/package.json
+++ b/dist/cjs/package.json
@@ -1,5 +1,5 @@
 {
   "name": "average-rating-cjs",
-  "version": "2.0.0",
+  "version": "2.0.1",
   "main": "./average-rating.js"
 }
\ No newline at end of file
diff --git a/eval.js b/eval.js
new file mode 100644
index 0000000..b185bc9
--- /dev/null
+++ b/eval.js
@@ -0,0 +1,14 @@
+// eval.js
+
+import {
+  score,
+  rate,
+  average
+} from './src/main.js'
+
+const scoring = [80, 20]
+const rating = [134055, 57472, 143135, 365957, 1448459]
+
+console.log(`score(${scoring.join(', ')}) // => ${score(...scoring)}`)
+console.log(`average([${rating.join(', ')}]) // => ${average(rating)}`)
+console.log(`rate([${rating.join(', ')}]) // => ${rate(rating)}`)
diff --git a/package.json b/package.json
index a3716df..a07fa9c 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "2.0.0",
+  "version": "2.0.1",
   "name": "average-rating",
   "description": "Calculate average score and rating based on Wilson Score Equation",
   "homepage": "https://www.npmjs.com/package/average-rating",
@@ -16,12 +16,18 @@
     "node": ">= 14"
   },
   "scripts": {
-    "lint": "standard ./src",
-    "pretest": "npm run lint && npm run build",
+    "lint": "standard .",
+    "pretest": "npm run lint",
     "test": "NODE_ENV=test jest --verbose --coverage=true --unhandled-rejections=strict --detectOpenHandles",
-    "build": "node build.js src/main.js",
+    "build": "node build src/main.js",
+    "eval": "node eval",
     "reset": "node reset"
   },
+  "devDependencies": {
+    "@babel/plugin-transform-modules-commonjs": "^7.16.7",
+    "esbuild": "^0.14.10",
+    "jest": "^27.3.1"
+  },
   "babel": {
     "env": {
       "test": {
@@ -31,10 +37,10 @@
       }
     }
   },
-  "devDependencies": {
-    "@babel/plugin-transform-modules-commonjs": "^7.16.7",
-    "esbuild": "^0.14.10",
-    "jest": "^27.3.1"
+  "standard": {
+    "ignore": [
+      "/dist"
+    ]
   },
   "keywords": [
     "rating",