fix(fix): readme api

Author: iamkun

ReadMe.md

@@ -1,3 +1,4 @@
+English | [简体中文](./README.zh-CN.md)
 <p align="center"><a href="#" target="_blank" rel="noopener noreferrer"><img width="550"
                                                                              src="https://user-images.githubusercontent.com/17680888/39081119-3057bbe2-456e-11e8-862c-646133ad4b43.png"
                                                                              alt="Day.js"></a></p>
@@ -19,11 +20,336 @@
 
 > Day.js is a minimalist JavaScript library for modern browsers with a largely Moment.js-compatible API. If you use Moment.js, you already know how to use Day.js.
 
-- Familiar Moment.js API & patterns
-- Immutable
-- Chainable
-- All browsers support
+```js
+dayjs().startOf('month').add(1, 'day').set('year', 2018).format('YYYY-MM-DD HH:mm:ss');
+```
+
+- 🕒 Familiar Moment.js API & patterns
+- 💪 Immutable
+- 🔥 Chainable
+- 📦 2kb mini library
+- 👫 All browsers support
+---
+
+## Installation
+
+You have multiple ways of getting Day.js:
+
+- Via NPM:
+```console
+    npm install dayjs --save
+```
+```js
+    var dayjs = require('dayjs');
+    dayjs().format();
+```
+- Via CDN:
+```html
+    <!-- Latest compiled and minified JavaScript -->
+    <script src="https://unpkg.com/dayjs"></script>
+    <script>
+      dayjs().format();
+    </script>
+```
+
+- Via download and self-hosting:
+
+Just download the latest version of Day.js at [https://unpkg.com/dayjs](https://unpkg.com/dayjs)
+
+## Getting Started
+Instead of modifying the native `Date.prototype`, Day.js creates a wrapper for the Date object, called `Dayjs` object.
+`Dayjs` object is inmmutable, that is to say, all api operation will return a new `Dayjs` object.
+
+## API
+
+Api will always return a new `Dayjs` object if not specified. 
+
+* [Parse](#parse)
+  * [Now](#now)
+  * [String](#string)
+  * [Unix Timestamp (milliseconds)](#unix-timestamp-milliseconds)
+  * [Date](#date)
+  * [Clone](#clone)
+  * [Validation](#validation)
+* [Get + Set](#get--set)
+  * [Year](#year)
+  * [Month](#month)
+  * [Date of Month](#date-1)
+  * [Hour](#hour)
+  * [Minute](#minute)
+  * [Second](#second)
+  * [Millisecond](#millisecond)
+  * [Set](#set)
+* [Manipulate](#manipulate)
+  * [Add](#add)
+  * [Subtract](#subtract)
+  * [Start of Time](#start-of-time)
+  * [End of Time](#end-of-time)
+* [Display](#display)
+  * [Format](#format)
+  * [Difference](#different)
+  * [Unix Timestamp (milliseconds)](#unix-timestamp-milliseconds-1)
+  * [Unix Timestamp (seconds)](#unix-timestamp-seconds)
+  * [Days in Month](#days-in-month)
+  * [As Javascript Date](#as-javascript-date)
+  * [As Array](#as-array)
+  * [As JSON](#as-json)
+  * [As ISO 8601 String](#as-ios-8601-string)
+  * [As Object](#as-object)
+  * [As String](#as-string)
+* [Query](#query)
+  * [Is Before](#is-before)
+  * [Is Same](#is-same)
+  * [Is After](#is-after)
+  * [Is Leap Year](#is-leap-year)
+
+---
+### Parse
+Simply call `dayjs()` with one of the supported input types.
+#### Now
+To get the current date and time, just call dayjs() with no parameters.
+```js
+dayjs();
+```
+### String
+Creating from a string matches [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) format.
+```js
+dayjs(String);
+dayjs("1995-12-25");
+```
+### Unix Timestamp (milliseconds)
+Passing an integer value representing the number of milliseconds since the Unix Epoch (Jan 1 1970 12AM UTC).
+```js
+dayjs(Number);
+dayjs(1318781876406);
+```
+### Date
+Passing a pre-existing native Javascript Date object.
+```js
+dayjs(Date);
+dayjs(new Date(2018, 8, 18));
+```
+### Clone
+All `Dayjs` are inmmutable. If you want a copy of the object, just call `.clone()`.
+Calling dayjs() on a `Dayjs` object will also clone it.
+```js
+dayjs(Dayjs);
+dayjs().clone();
+```
+### Validation
+- return Boolean
+
+Check whether the `Dayjs` object considers the date invalid.
+```js
+dayjs().isValid();
+```
+---
+### Get + Set
+Get and set date.
+#### Year
+- return Number
+
+Get year.
+```js
+dayjs().year();
+```
+#### Month
+- return Number
+
+Get month.
+```js
+dayjs().month();
+```
+#### Date of Month
+- return Number
+
+Get day of the month.
+```js
+dayjs().date();
+```
+#### Hour
+- return Number
+
+Get hour.
+```js
+dayjs().hour();
+```
+#### Minute
+- return Number
+
+Get minute.
+```js
+dayjs().minute();
+```
+#### Second
+- return Number
+
+Get second.
+```js
+dayjs().second();
+```
+#### Millisecond
+- return Number
+
+Get millisecond.
+```js
+dayjs().millisecond();
+```
+#### Set
+Date setter.
+Units are case insensitive
+```js
+dayjs().set(unit : String, value : Int);
+dayjs().set('month', 3);  // April
+moment().set('second', 30);
+```
+---
+### Manipulate
+Once you have a `Dayjs` object, you may want to manipulate it in some way like this:
+```js
+dayjs().startOf('month').add(1, 'day').subtract(1, 'year')
+```
+#### Add
+Return a new `Dayjs` object by adding time.
+```js
+dayjs().add(value : Number, unit : String);
+dayjs().add(7, 'day');
+```
+#### Subtract
+Return a new `Dayjs` object by subtracting time. exactly the same as `dayjs#add`.
+```js
+dayjs().subtract(value : Number, unit : String);
+dayjs().subtract(7, 'year');
+```
+#### Start of Time
+Return a new `Dayjs` object by by setting it to the start of a unit of time.
+```js
+dayjs().startOf(unit : String);
+dayjs().startOf('year');
+```
+#### End of Time
+Return a new `Dayjs` object by by setting it to the end of a unit of time.
+```js
+dayjs().endOf(unit : String);
+dayjs().endOf('month');
+```
+---
+### Display
+Once parsing and manipulation are done, you need some way to display the `Dayjs` object.
+#### Format
+- return String
+
+This is the most robust display option. It takes a string of tokens and replaces them with their corresponding values.
+```js
+dayjs().format(String);
+dayjs().format();                       // "2014-09-08T08:02:17-05:00" (ISO 8601, no fractional seconds)
+dayjs().format("[YYYY] MM-DDTHH:mm:ssZ"); // "[2014] 09-08T08:02:17-05:00"
+```
+#### Difference
+- return Number
+
+To get the difference of two `Dayjs` object in milliseconds or other unit.
+```js
+dayjs().diff(Dayjs, unit);
+dayjs().diff(dayjs(), 'years'); // 0
+```
+#### Unix Timestamp (milliseconds)
+- return Number
+
+Outputs the number of milliseconds since the Unix Epoch
+```js
+dayjs().valueOf();
+```
+#### Unix Timestamp (seconds)
+- return Number
+
+Outputs a Unix timestamp (the number of seconds since the Unix Epoch).
+```js
+dayjs().unix();
+```
+#### Days in Month
+- return Number
+
+Get the number of days in the current month.
+```js
+dayjs().daysInMonth();
+```
+#### As Javascript Date
+- return Javascript `Date` object
+
+Get copy of the native `Date` object from `Dayjs` object.
+```js
+dayjs().toDate();
+```
+#### As Array
+- return Array
+
+Return an array that mirrors the parameters from new Date().
+```js
+dayjs().toArray(); //[2018, 8, 18, 00, 00, 00, 000];
+```
+#### As JSON
+- return JSON String
+
+Serializing an `Dayjs` to JSON, will return an ISO8601 string.
+```js
+dayjs().toJSON(); //"2018-08-08T00:00:00.000Z"
+```
+#### As ISO 8601 String
+- return String
+
+Formats a string to the ISO8601 standard.
+```js
+dayjs().toISOString();
+```
+#### As Object
+- return Object 
+
+Return an object with year, month ... missisecond.
+```js
+dayjs().toObject();// { years:2018, months:8, date:18, hours:0, minutes:0, seconds:0, milliseconds:0}
+```
+#### As String
+- return String 
+
+```js
+dayjs().toString(); 
+```
+---
+### Query
+#### Is Before
+- return Boolean
+
+Check if a `Dayjs` object is before another `Dayjs` object. 
+```js
+dayjs().isBefore(Dayjs);
+dayjs().isBefore(dayjs()); // false
+```
+#### Is Same
+- return Boolean
+
+Check if a `Dayjs` object is same as another `Dayjs` object. 
+```js
+dayjs().isSame(Dayjs);
+dayjs().isSame(dayjs()); // true
+```
+#### Is After
+- return Boolean
+
+Check if a `Dayjs` object is after another `Dayjs` object. 
+```js
+dayjs().isAfter(Dayjs);
+dayjs().isAfter(dayjs()); // false
+```
+#### Is Leap Year
+- return Boolean
+
+Check if a year is a leap year. 
+```js
+dayjs().isLeapYear();
+dayjs('2000-01-01').isLeapYear(dayjs()); // true
+```
 ---
 ## License
 
-MIT
+MIT