Adding prettier (#49)

.eslintrc.js

@@ -0,0 +1,49 @@
+module.exports = {
+  extends: [
+    'prettier',
+    'eslint:recommended',
+    'plugin:flowtype/recommended',
+    'prettier/flowtype',
+  ],
+  parser: 'babel-eslint',
+  plugins: ['prettier', 'jest', 'flowtype'],
+  env: {
+    node: true,
+    browser: true,
+    es6: true,
+    'jest/globals': true,
+  },
+  // custom rules
+  rules: {
+    // Error on prettier violations
+    'prettier/prettier': 'error',
+
+    // New eslint style rules that is not disabled by prettier:
+    'lines-between-class-members': 'off',
+
+    // Allowing warning and error console logging
+    // use `invariant` and `warning`
+    'no-console': ['error'],
+
+    // Opting out of prefer destructuring (nicer with flow in lots of cases)
+    'prefer-destructuring': 'off',
+
+    // Disallowing the use of variables starting with `_` unless it called on `this`.
+    // Allowed: `this._secret = Symbol()`
+    // Not allowed: `const _secret = Symbol()`
+    'no-underscore-dangle': ['error', { allowAfterThis: true }],
+
+    // Cannot reassign function parameters but allowing modification
+    'no-param-reassign': ['error', { props: false }],
+
+    // Allowing ++ on numbers
+    'no-plusplus': 'off',
+
+    // Require // @flow at the top of files
+    'flowtype/require-valid-file-annotation': [
+      'error',
+      'always',
+      { annotationStyle: 'line' },
+    ],
+  },
+};

.prettierignore

@@ -0,0 +1 @@
+/node_modules/*

.prettierrc

@@ -0,0 +1,7 @@
+{
+  "trailingComma": "all",
+  "semi": true,
+  "tabWidth": 2,
+  "useTabs": false,
+  "singleQuote": true
+}

README.md

@@ -91,15 +91,15 @@ const identity = x => x;
 const defaultMemoization = memoizeOne(identity);
 const customMemoization = memoizeOne(identity, deepEqual);
 
-const result1 = defaultMemoization({foo: 'bar'});
-const result2 = defaultMemoization({foo: 'bar'});
+const result1 = defaultMemoization({ foo: 'bar' });
+const result2 = defaultMemoization({ foo: 'bar' });
 
-result1 === result2 // false - difference reference
+result1 === result2; // false - difference reference
 
-const result3 = customMemoization({foo: 'bar'});
-const result4 = customMemoization({foo: 'bar'});
+const result3 = customMemoization({ foo: 'bar' });
+const result4 = customMemoization({ foo: 'bar' });
 
-result3 === result4 // true - arguments are deep equal
+result3 === result4; // true - arguments are deep equal
 ```
 
 ### Custom equality function behaviour
@@ -129,7 +129,11 @@ Here is an example of a higher order function that allow you to pass an `index`
 
 ```js
 // this function will do some special checking for the second argument
-const customIsEqual = (newValue: mixed, oldValue: mixed, index: number): boolean => {
+const customIsEqual = (
+  newValue: mixed,
+  oldValue: mixed,
+  index: number,
+): boolean => {
   if (index === 1) {
     if (!isDate(newValue) || !isDate(oldValue)) {
       return false;
@@ -142,7 +146,8 @@ const customIsEqual = (newValue: mixed, oldValue: mixed, index: number): boolean
 
 const getMemoizedWithIndex = (fn: Function) => {
   let argIndex: number = 0;
-  const withIndex = (newValue: mixed, oldValue: mixed) => customIsEqual(newValue, oldValue, argIndex++);
+  const withIndex = (newValue: mixed, oldValue: mixed) =>
+    customIsEqual(newValue, oldValue, argIndex++);
   const memoized = memoizeOne(fn, withIndex);
 
   // every time this function is called it will reset our argIndex
@@ -161,7 +166,12 @@ Here is an example of a higher order function that allow you to pass a `index` a
 
 ```js
 // using this to only memoize calls with 3+ arguments
-const customIsEqual = (newValue: mixed, oldValue: mixed, index: number, args: mixed[]): boolean => {
+const customIsEqual = (
+  newValue: mixed,
+  oldValue: mixed,
+  index: number,
+  args: mixed[],
+): boolean => {
   if (args.length < 3) {
     return false;
   }
@@ -170,7 +180,8 @@ const customIsEqual = (newValue: mixed, oldValue: mixed, index: number, args: mi
 const getMemoizedFn = (fn: Function) => {
   let args: mixed[] = [];
   let argIndex: number = 0;
-  const withIndex = (newValue: mixed, oldValue: mixed) => customIsEqual(newValue, oldValue, argIndex++, args);
+  const withIndex = (newValue: mixed, oldValue: mixed) =>
+    customIsEqual(newValue, oldValue, argIndex++, args);
   const memoized = memoizeOne(fn, withIndex);
 
   // every time this function is called it will reset our args and argIndex
@@ -211,15 +222,15 @@ const temp1 = {
 };
 const temp2 = {
   a: 30,
-}
+};
 
 getA.call(temp1); // 20
 getA.call(temp2); // 30
 ```
 
 Therefore, in order to prevent against unexpected results, `memoize-one` takes into account the current execution context (`this`) of the memoized function. If `this` is different to the previous invocation then it is considered a change in argument. [further discussion](https://github.com/alexreardon/memoize-one/issues/3).
 
-Generally this will be of no impact if you are not explicity controlling the `this` context of functions you want to memoize with [explicit binding](https://github.com/getify/You-Dont-Know-JS/blob/master/this%20%26%20object%20prototypes/ch2.md#explicit-binding)  or [implicit binding](https://github.com/getify/You-Dont-Know-JS/blob/master/this%20%26%20object%20prototypes/ch2.md#implicit-binding). `memoize-One` will detect when you are manipulating `this` and will then consider the `this` context as an argument. If `this` changes, it will re-execute the original function even if the arguments have not changed.
+Generally this will be of no impact if you are not explicity controlling the `this` context of functions you want to memoize with [explicit binding](https://github.com/getify/You-Dont-Know-JS/blob/master/this%20%26%20object%20prototypes/ch2.md#explicit-binding) or [implicit binding](https://github.com/getify/You-Dont-Know-JS/blob/master/this%20%26%20object%20prototypes/ch2.md#implicit-binding). `memoize-One` will detect when you are manipulating `this` and will then consider the `this` context as an argument. If `this` changes, it will re-execute the original function even if the arguments have not changed.
 
 ## When your result function `throw`s
 
@@ -230,11 +241,11 @@ If your result function `throw`s then the memoized function will also throw. The
 ```js
 const canThrow = (name: string) => {
   console.log('called');
-  if(name === 'throw') {
+  if (name === 'throw') {
     throw new Error(name);
   }
   return { name };
-}
+};
 
 const memoized = memoizeOne(canThrow);
 
@@ -249,7 +260,7 @@ console.log(value1 === value2);
 try {
   memoized('throw');
   // console.log => 'called'
-} catch(e) {
+} catch (e) {
   firstError = e;
 }
 
@@ -258,13 +269,12 @@ try {
   // console.log => 'called'
   // the result function was called again even though it was called twice
   // with the 'throw' string
-} catch(e) {
+} catch (e) {
   secondError = e;
 }
 
 console.log(firstError !== secondError);
 
-
 const value3 = memoized('Alex');
 // result function not called as the original memoization cache has not been busted
 console.log(value1 === value3);

package.json

@@ -23,30 +23,39 @@
   ],
   "dependencies": {},
   "devDependencies": {
-    "@babel/core": "^7.2.0",
+    "@babel/core": "^7.2.2",
     "@babel/preset-env": "^7.2.0",
     "@babel/preset-flow": "^7.0.0",
     "babel-core": "^7.0.0-bridge.0",
     "babel-eslint": "10.0.1",
     "babel-jest": "^23.6.0",
     "cross-env": "^5.2.0",
     "eslint": "5.10.0",
+    "eslint-config-prettier": "^3.3.0",
     "eslint-plugin-flowtype": "^3.2.0",
     "eslint-plugin-jest": "^22.1.2",
-    "flow-bin": "0.88.0",
+    "eslint-plugin-prettier": "^3.0.0",
+    "flow-bin": "0.89.0",
     "jest": "^23.6.0",
+    "prettier": "1.15.3",
     "rimraf": "2.6.2",
-    "rollup": "^0.67.4",
-    "rollup-plugin-babel": "^4.0.3",
+    "rollup": "^0.68.0",
+    "rollup-plugin-babel": "^4.1.0",
     "rollup-plugin-commonjs": "^9.2.0",
     "rollup-plugin-replace": "^2.1.0",
     "rollup-plugin-uglify": "^6.0.0"
   },
+  "config": {
+    "prettier_target": "*.{js,jsx,md,json} src/**/*.{js,jsx,md,json} test/**/*.{js,jsx,md,json}"
+  },
   "scripts": {
     "validate": "yarn run lint && yarn run typecheck",
     "test": "cross-env NODE_ENV=test jest",
     "typecheck": "flow check",
-    "lint": "eslint src test",
+    "prettier:check": "yarn prettier --debug-check $npm_package_config_prettier_target",
+    "prettier:write": "yarn prettier --write $npm_package_config_prettier_target",
+    "lint:eslint": "eslint src test",
+    "lint": "yarn lint:eslint && yarn prettier:check",
     "build": "yarn run build:clean && yarn run build:dist && yarn run build:flow",
     "build:clean": "rimraf dist",
     "build:dist": "rollup -c",