diff --git a/docs/en/API-reference.md b/docs/en/API-reference.md
index 5d21d2ffb..1bcb3a625 100644
--- a/docs/en/API-reference.md
+++ b/docs/en/API-reference.md
@@ -43,14 +43,16 @@ The `Dayjs` object is immutable, that is, all API operations that change the `Da
     - [As Object `.toObject()`](#as-object-toobject)
     - [As String `.toString()`](#as-string-tostring)
   - [Query](#query)
-    - [Is Before `.isBefore(compared: Dayjs)`](#is-before-isbeforecompared-dayjs)
-    - [Is Same `.isSame(compared: Dayjs)`](#is-same-issamecompared-dayjs)
-    - [Is After `.isAfter(compared: Dayjs)`](#is-after-isaftercompared-dayjs)
+    - [Is Before `.isBefore(compared: Dayjs, unit?: string)`](#is-before-isbeforecompared-dayjs-unit-string)
+    - [Is Same `.isSame(compared: Dayjs, unit?: string)`](#is-same-issamecompared-dayjs-unit-string)
+    - [Is After `.isAfter(compared: Dayjs, unit?: string)`](#is-after-isaftercompared-dayjs-unit-string)
     - [Is a Dayjs `.isDayjs()`](#is-a-dayjs-isdayjscompared-any)
   - [Plugin APIs](#plugin-apis)
     - [RelativeTime](#relativetime)
     - [IsLeapYear](#isleapyear)
     - [WeekOfYear](#weekofyear)
+    - [IsSameOrAfter](#issameorafter)
+    - [IsSameOrBefore](#issameorbefore)
     - [IsBetween](#isbetween)
 
 ## Parsing
@@ -383,28 +385,31 @@ dayjs('2019-01-25').toString(); // 'Fri, 25 Jan 2019 02:00:00 GMT'
 
 ## Query
 
-### Is Before `.isBefore(compared: Dayjs)`
+### Is Before `.isBefore(compared: Dayjs, unit?: string)`
 
 Returns a `boolean` indicating whether the `Dayjs`'s date is before the other supplied `Dayjs`'s.
 
 ```js
 dayjs().isBefore(dayjs()); // false
+dayjs().isBefore(dayjs(), 'year'); // false
 ```
 
-### Is Same `.isSame(compared: Dayjs)`
+### Is Same `.isSame(compared: Dayjs, unit?: string)`
 
 Returns a `boolean` indicating whether the `Dayjs`'s date is the same as the other supplied `Dayjs`'s.
 
 ```js
 dayjs().isSame(dayjs()); // true
+dayjs().isSame(dayjs(), 'year'); // true
 ```
 
-### Is After `.isAfter(compared: Dayjs)`
+### Is After `.isAfter(compared: Dayjs, unit?: string)`
 
 Returns a `boolean` indicating whether the `Dayjs`'s date is after the other supplied `Dayjs`'s.
 
 ```js
 dayjs().isAfter(dayjs()); // false
+dayjs().isAfter(dayjs(), 'year'); // false
 ```
 
 ### Is a Dayjs `.isDayjs(compared: any)`
@@ -436,6 +441,18 @@ plugin [`IsLeapYear`](./Plugin.md#isleapyear)
 
 plugin [`WeekOfYear`](./Plugin.md#weekofyear)
 
+### IsSameOrAfter
+
+`.isSameOrAfter` to check if a date is same of after another date
+
+plugin [`IsSameOrAfter`](./Plugin.md#issameorafter)
+
+### IsSameOrBefore
+
+`.isSameOrBefore` to check if a date is same of before another date.
+
+plugin [`IsSameOrBefore`](./Plugin.md#issameorbefore)
+
 ### IsBetween
 
 `.isBetween` to check if a date is between two other dates
diff --git a/docs/en/Plugin.md b/docs/en/Plugin.md
index 2660013f7..ffbf86c21 100644
--- a/docs/en/Plugin.md
+++ b/docs/en/Plugin.md
@@ -155,6 +155,28 @@ dayjs.extend(weekOfYear)
 dayjs('06/27/2018').week() // 26
 ```
 
+### IsSameOrAfter
+ - IsSameOrAfter adds `.isSameOrAfter()` API to returns a `boolean` indicating if a date is same of after another date.
+
+```javascript
+import isSameOrAfter from 'dayjs/plugin/isSameOrAfter'
+
+dayjs.extend(isSameOrAfter)
+
+dayjs('2010-10-20').isSameOrAfter('2010-10-19', 'year');
+```
+
+### IsSameOrBefore
+ - IsSameOrBefore adds `.isSameOrBefore()` API to returns a `boolean` indicating if a date is same of before another date.
+
+```javascript
+import isSameOrBefore from 'dayjs/plugin/isSameOrBefore'
+
+dayjs.extend(isSameOrBefore)
+
+dayjs('2010-10-20').isSameOrBefore('2010-10-19', 'year');
+```
+
 ### IsBetween
  - IsBetween adds `.isBetween()` API to returns a `boolean` indicating if a date is between two other dates.
 
@@ -163,7 +185,7 @@ import isBetween from 'dayjs/plugin/isBetween'
 
 dayjs.extend(isBetween)
 
-dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25')); // true
+dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25'), 'year');
 ```
 
 ## Customize
diff --git a/docs/es-es/API-reference.md b/docs/es-es/API-reference.md
index 2fc5b0660..2926c0df3 100644
--- a/docs/es-es/API-reference.md
+++ b/docs/es-es/API-reference.md
@@ -43,14 +43,16 @@ El objeto `Dayjs` es inmutable, por lo que toda operación de la API que altere
     - [Como objeto `.toObject()`](#como-objecto-toobject)
     - [Como cadena `.toString()`](#como-cadena-tostring)
   - [Consulta](#consulta)
-    - [Anterior a `.isBefore(compared: Dayjs)`](#anterior-a-isbeforecompared-dayjs)
-    - [Igual que `.isSame(compared: Dayjs)`](#igual-que-issamecompared-dayjs)
-    - [Posterior a `.isAfter(compared: Dayjs)`](#posterior-a-isaftercompared-dayjs)
+    - [Anterior a `.isBefore(compared: Dayjs, unit?: string)`](#anterior-a-isbeforecompared-dayjs-unit-string)
+    - [Igual que `.isSame(compared: Dayjs, unit?: string)`](#igual-que-issamecompared-dayjs-unit-string)
+    - [Posterior a `.isAfter(compared: Dayjs, unit?: string)`](#posterior-a-isaftercompared-dayjs-unit-string)
     - [Es Dayjs `.isDayjs()`](#es-dayjs-isdayjscompared-any)
   - [API de complementos](#api-de-complementos)
     - [RelativeTime](#relativetime)
     - [IsLeapYear](#isleapyear)
     - [WeekOfYear](#weekofyear)
+    - [IsSameOrAfter](#issameorafter)
+    - [IsSameOrBefore](#issameorbefore)
     - [IsBetween](#isbetween)
 
 ## Análisis
@@ -383,28 +385,31 @@ dayjs('2019-01-25').toString(); // 'Fri, 25 Jan 2019 02:00:00 GMT'
 
 ## Consulta
 
-### Anterior a `.isBefore(compared: Dayjs)`
+### Anterior a `.isBefore(compared: Dayjs, unit?: string)`
 
 Devuelve un dato de tipo `boolean`, que indica si la fecha del objeto `Dayjs` inicial es anterior o no a la fecha del objeto `Dayjs` a comparar.
 
 ```js
 dayjs().isBefore(dayjs()); // false
+dayjs().isBefore(dayjs(), 'year'); // false
 ```
 
-### Igual que `.isSame(compared: Dayjs)`
+### Igual que `.isSame(compared: Dayjs, unit?: string)`
 
 Devuelve un dato de tipo `boolean`, que indica si la fecha del objeto `Dayjs` inicial es igual o no que la fecha del objeto `Dayjs` a comparar.
 
 ```js
 dayjs().isSame(dayjs()); // true
+dayjs().isSame(dayjs(), 'year'); // true
 ```
 
-### Posterior a `.isAfter(compared: Dayjs)`
+### Posterior a `.isAfter(compared: Dayjs, unit?: string)`
 
 Devuelve un dato de tipo `boolean`, que indica si la fecha del objeto `Dayjs` inicial es posterior o no a la fecha del objeto `Dayjs` a comparar.
 
 ```js
 dayjs().isAfter(dayjs()); // false
+dayjs().isAfter(dayjs(), 'year'); // false
 ```
 
 ### Es Dayjs `.isDayjs(compared: any)`
@@ -436,6 +441,18 @@ complemento [`IsLeapYear`](./Plugin.md#isleapyear)
 
 complemento [`WeekOfYear`](./Plugin.md#weekofyear)
 
+### IsSameOrAfter
+
+`.isSameOrAfter` to check if a date is same of after another date
+
+plugin [`IsSameOrAfter`](./Plugin.md#issameorafter)
+
+### IsSameOrBefore
+
+`.isSameOrBefore` to check if a date is same of before another date.
+
+plugin [`IsSameOrBefore`](./Plugin.md#issameorbefore)
+
 ### IsBetween
 
 `.isBetween` para comprobar si una fecha se encuentra entre otras dos fechas dadas
diff --git a/docs/es-es/Plugin.md b/docs/es-es/Plugin.md
index f5e702932..bf492b342 100644
--- a/docs/es-es/Plugin.md
+++ b/docs/es-es/Plugin.md
@@ -161,6 +161,28 @@ dayjs.extend(weekOfYear)
 dayjs('06/27/2018').week() // 26
 ```
 
+### IsSameOrAfter
+ - IsSameOrAfter adds `.isSameOrAfter()` API to returns a `boolean` indicating if a date is same of after another date.
+
+```javascript
+import isSameOrAfter from 'dayjs/plugin/isSameOrAfter'
+
+dayjs.extend(isSameOrAfter)
+
+dayjs('2010-10-20').isSameOrAfter('2010-10-19', 'year');
+```
+
+### IsSameOrBefore
+ - IsSameOrBefore adds `.isSameOrBefore()` API to returns a `boolean` indicating if a date is same of before another date.
+
+```javascript
+import isSameOrBefore from 'dayjs/plugin/isSameOrBefore'
+
+dayjs.extend(isSameOrBefore)
+
+dayjs('2010-10-20').isSameOrBefore('2010-10-19', 'year');
+```
+
 ### IsBetween
 
 * IsBetween añade la API `.isBetween()`, que devuelve un dato de tipo `boolean` indicando si una fecha se encuentra o no entre otras dos dadas.
@@ -170,7 +192,7 @@ import isBetween from 'dayjs/plugin/isBetween'
 
 dayjs.extend(isBetween)
 
-dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25')); // true
+dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25'), 'year');
 ```
 
 ## Personalización
diff --git a/docs/ja/API-reference.md b/docs/ja/API-reference.md
index a181b3750..f35be32b7 100644
--- a/docs/ja/API-reference.md
+++ b/docs/ja/API-reference.md
@@ -48,6 +48,8 @@ Day.js は組み込みの `Date.prototype` を変更する代わりに `Dayjs` 
   * [RelativeTime](#relativetime)
   * [IsLeapYear](#isleapyear)
   * [WeekOfYear](#weekofyear)
+  * [IsSameOrAfter](#issameorafter)
+  * [IsSameOrBefore](#issameorbefore)
   * [IsBetween](#isbetween)
 
 ---
@@ -451,8 +453,9 @@ dayjs().toString();
 `Dayjs` オブジェクトが別の `Dayjs` オブジェクト以前の値かどうかを判定します。
 
 ```js
-dayjs().isBefore(Dayjs);
+dayjs().isBefore(Dayjs, unit? : String);
 dayjs().isBefore(dayjs()); // false
+dayjs().isBefore(dayjs(), 'year'); // false
 ```
 
 #### Is Same
@@ -462,8 +465,9 @@ dayjs().isBefore(dayjs()); // false
 `Dayjs` オブジェクトが別の `Dayjs` オブジェクトの値と等しいかどうかを判定します。
 
 ```js
-dayjs().isSame(Dayjs);
+dayjs().isSame(Dayjs, unit? : String);
 dayjs().isSame(dayjs()); // true
+dayjs().isSame(dayjs(), 'year'); // true
 ```
 
 #### Is After
@@ -473,8 +477,9 @@ dayjs().isSame(dayjs()); // true
 `Dayjs` オブジェクトが別の `Dayjs` オブジェクト以降の値かどうかを判定します。
 
 ```js
-dayjs().isAfter(Dayjs);
+dayjs().isAfter(Dayjs, unit? : String);
 dayjs().isAfter(dayjs()); // false
+dayjs().isAfter(dayjs(), 'year'); // false
 ```
 
 ### Is a Dayjs `.isDayjs(compared: any)`
@@ -506,6 +511,18 @@ plugin [`IsLeapYear`](./Plugin.md#isleapyear)
 
 plugin [`WeekOfYear`](./Plugin.md#weekofyear)
 
+### IsSameOrAfter
+
+`.isSameOrAfter` to check if a date is same of after another date
+
+plugin [`IsSameOrAfter`](./Plugin.md#issameorafter)
+
+### IsSameOrBefore
+
+`.isSameOrBefore` to check if a date is same of before another date.
+
+plugin [`IsSameOrBefore`](./Plugin.md#issameorbefore)
+
 ### IsBetween
 
 `.isBetween` to check if a date is between two other dates
diff --git a/docs/ja/Plugin.md b/docs/ja/Plugin.md
index a1886bb7d..319960384 100644
--- a/docs/ja/Plugin.md
+++ b/docs/ja/Plugin.md
@@ -155,6 +155,27 @@ dayjs.extend(weekOfYear)
 
 dayjs('06/27/2018').week() // 26
 ```
+### IsSameOrAfter
+ - IsSameOrAfter adds `.isSameOrAfter()` API to returns a `boolean` indicating if a date is same of after another date.
+
+```javascript
+import isSameOrAfter from 'dayjs/plugin/isSameOrAfter'
+
+dayjs.extend(isSameOrAfter)
+
+dayjs('2010-10-20').isSameOrAfter('2010-10-19', 'year');
+```
+
+### IsSameOrBefore
+ - IsSameOrBefore adds `.isSameOrBefore()` API to returns a `boolean` indicating if a date is same of before another date.
+
+```javascript
+import isSameOrBefore from 'dayjs/plugin/isSameOrBefore'
+
+dayjs.extend(isSameOrBefore)
+
+dayjs('2010-10-20').isSameOrBefore('2010-10-19', 'year');
+```
 
 ### IsBetween
  - IsBetween adds `.isBetween()` API to returns a `boolean` indicating if a date is between two other dates.
@@ -164,7 +185,7 @@ import isBetween from 'dayjs/plugin/isBetween'
 
 dayjs.extend(isBetween)
 
-dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25')); // true
+dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25'), 'year');
 ```
 
 ## カスタマイズ
diff --git a/docs/ko/API-reference.md b/docs/ko/API-reference.md
index 99a5c7c7f..3f7d82529 100644
--- a/docs/ko/API-reference.md
+++ b/docs/ko/API-reference.md
@@ -42,14 +42,16 @@ Day.js는 네이티브 `Date.prototype`을 수정하는 대신 `Dayjs` 오브젝
     - [As Object `.toObject()`](#as-object-toobject)
     - [As String `.toString()`](#as-string-tostring)
   - [Query](#query)
-    - [Is Before `.isBefore(compared: Dayjs)`](#is-before-isbeforecompared--dayjs)
-    - [Is Same `.isSame(compared: Dayjs)`](#is-same-issamecompared--dayjs)
-    - [Is After `.isAfter(compared: Dayjs)`](#is-after-isaftercompared--dayjs)
+    - [Is Before `.isBefore(compared: Dayjs, unit?: string)`](#is-before-isbeforecompared--dayjs-unit-string)
+    - [Is Same `.isSame(compared: Dayjs, unit?: string)`](#is-same-issamecompared--dayjs-unit-string)
+    - [Is After `.isAfter(compared: Dayjs, unit?: string)`](#is-after-isaftercompared--dayjs-unit-string)
     - [Is a Dayjs `.isDayjs()`](#is-a-dayjs-isdayjscompared-any)
   - [Plugin APIs](#plugin-apis)
     - [RelativeTime](#relativetime)
     - [IsLeapYear](#isleapyear)
     - [WeekOfYear](#weekofyear)
+    - [IsSameOrAfter](#issameorafter)
+    - [IsSameOrBefore](#issameorbefore)
     - [IsBetween](#isbetween)
 
 ## Parsing
@@ -382,28 +384,31 @@ dayjs('2019-01-25').toString(); // 'Fri, 25 Jan 2019 02:00:00 GMT'
 
 ## Query
 
-### Is Before `.isBefore(compared: Dayjs)`
+### Is Before `.isBefore(compared: Dayjs, unit?: string)`
 
 `Dayjs`가 다른 `Dayjs`보다 앞선 시점인지를 확인합니다. 반환 타입은 `boolean` 입니다.
 
 ```js
 dayjs().isBefore(dayjs()); // false
+dayjs().isBefore(dayjs(), 'year'); // false
 ```
 
-### Is Same `.isSame(compared: Dayjs)`
+### Is Same `.isSame(compared: Dayjs, unit?: string)`
 
 `Dayjs`가 다른 `Dayjs`과 동일한 시점인지를 확인합니다. 반환 타입은 `boolean` 입니다.
 
 ```js
 dayjs().isSame(dayjs()); // true
+dayjs().isSame(dayjs(), 'year'); // true
 ```
 
-### Is After `.isAfter(compared: Dayjs)`
+### Is After `.isAfter(compared: Dayjs, unit?: string)`
 
 `Dayjs`가 다른 `Dayjs`보다 뒷선 시점인지를 확인합니다. 반환 타입은 `boolean` 입니다.
 
 ```js
 dayjs().isAfter(dayjs()); // false
+dayjs().isAfter(dayjs(), 'year'); // false
 ```
 
 ### Is a Dayjs `.isDayjs(compared: any)`
@@ -435,6 +440,18 @@ plugin [`IsLeapYear`](./Plugin.md#isleapyear)
 
 plugin [`WeekOfYear`](./Plugin.md#weekofyear)
 
+### IsSameOrAfter
+
+`.isSameOrAfter` to check if a date is same of after another date
+
+plugin [`IsSameOrAfter`](./Plugin.md#issameorafter)
+
+### IsSameOrBefore
+
+`.isSameOrBefore` to check if a date is same of before another date.
+
+plugin [`IsSameOrBefore`](./Plugin.md#issameorbefore)
+
 ### IsBetween
 
 `.isBetween` to check if a date is between two other dates
diff --git a/docs/ko/Plugin.md b/docs/ko/Plugin.md
index 8a2c3206f..195097760 100644
--- a/docs/ko/Plugin.md
+++ b/docs/ko/Plugin.md
@@ -155,6 +155,28 @@ dayjs.extend(weekOfYear)
 dayjs('06/27/2018').week() // 26
 ```
 
+### IsSameOrAfter
+ - IsSameOrAfter adds `.isSameOrAfter()` API to returns a `boolean` indicating if a date is same of after another date.
+
+```javascript
+import isSameOrAfter from 'dayjs/plugin/isSameOrAfter'
+
+dayjs.extend(isSameOrAfter)
+
+dayjs('2010-10-20').isSameOrAfter('2010-10-19', 'year');
+```
+
+### IsSameOrBefore
+ - IsSameOrBefore adds `.isSameOrBefore()` API to returns a `boolean` indicating if a date is same of before another date.
+
+```javascript
+import isSameOrBefore from 'dayjs/plugin/isSameOrBefore'
+
+dayjs.extend(isSameOrBefore)
+
+dayjs('2010-10-20').isSameOrBefore('2010-10-19', 'year');
+```
+
 ### IsBetween
  - IsBetween adds `.isBetween()` API to returns a `boolean` indicating if a date is between two other dates.
 
@@ -163,7 +185,7 @@ import isBetween from 'dayjs/plugin/isBetween'
 
 dayjs.extend(isBetween)
 
-dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25')); // true
+dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25'), 'year');
 ```
 
 ## Customize
diff --git a/docs/pt-br/API-reference.md b/docs/pt-br/API-reference.md
index 60414ae5e..b2f594fde 100644
--- a/docs/pt-br/API-reference.md
+++ b/docs/pt-br/API-reference.md
@@ -43,14 +43,16 @@ O objeto `Dayjs` é imutável, ou seja, todas as operações da API que alteram
     - [Como Objeto `.toObject()`](#como-objeto-toobject)
     - [Como String `.toString()`](#como-string-tostring)
   - [Consulta](#consulta)
-    - [Antes `.isBefore(compared: Dayjs)`](#antes-isbeforecompared-dayjs)
-    - [Igual `.isSame(compared: Dayjs)`](#igual-issamecompared-dayjs)
-    - [Depois `.isAfter(compared: Dayjs)`](#depois-isaftercompared-dayjs)
+    - [Antes `.isBefore(compared: Dayjs, unit?: string)`](#antes-isbeforecompared-dayjs-unit-string)
+    - [Igual `.isSame(compared: Dayjs, unit?: string)`](#igual-issamecompared-dayjs-unit-string)
+    - [Depois `.isAfter(compared: Dayjs, unit?: string)`](#depois-isaftercompared-dayjs-unit-string)
     - [É um objeto `Dayjs` `.isDayjs()`](#é-um-objeto-dayjs-isdayjs)
   - [Plugin APIs](#plugin-apis)
     - [RelativeTime](#relativetime)
     - [IsLeapYear](#isleapyear)
     - [WeekOfYear](#weekofyear)
+    - [IsSameOrAfter](#issameorafter)
+    - [IsSameOrBefore](#issameorbefore)
     - [IsBetween](#isbetween)
 
 ## Conversões
@@ -381,28 +383,31 @@ dayjs('2019-01-25').toString(); // 'Fri, 25 Jan 2019 02:00:00 GMT'
 
 ## Consulta
 
-### Antes `.isBefore(compared: Dayjs)`
+### Antes `.isBefore(compared: Dayjs, unit?: string)`]
 
 Retorna um `boolean` indicando se a data do objeto `Dayjs` é antes da data fornecida de em outro objeto `Dayjs`.
 
 ```js
 dayjs().isBefore(dayjs()); // false
+dayjs().isBefore(dayjs(), 'year'); // false
 ```
 
-### Igual `.isSame(compared: Dayjs)`
+### Igual `.isSame(compared: Dayjs, unit?: string)`]
 
 Retorna um `boolean` indicando se a data do objeto `Dayjs` é a mesma data fornecida de em outro objeto `Dayjs`.
 
 ```js
-dayjs().isBefore(dayjs()); // false
+dayjs().isSame(dayjs()); // true
+dayjs().isSame(dayjs(), 'year'); // true
 ```
 
-### Depois `.isAfter(compared: Dayjs)`
+### Depois `.isAfter(compared: Dayjs, unit?: string)`]
 
 Retorna um `boolean` indicando se a data do objeto `Dayjs` é depois da data fornecida de em outro objeto `Dayjs`.
 
 ```js
 dayjs().isAfter(dayjs()); // false
+dayjs().isAfter(dayjs(), 'year'); // false
 ```
 
 ### É um objeto `Dayjs` `.isDayjs()`
@@ -434,6 +439,18 @@ plugin [`IsLeapYear`](./Plugin.md#isleapyear)
 
 plugin [`WeekOfYear`](./Plugin.md#weekofyear)
 
+### IsSameOrAfter
+
+`.isSameOrAfter` to check if a date is same of after another date
+
+plugin [`IsSameOrAfter`](./Plugin.md#issameorafter)
+
+### IsSameOrBefore
+
+`.isSameOrBefore` to check if a date is same of before another date.
+
+plugin [`IsSameOrBefore`](./Plugin.md#issameorbefore)
+
 ### IsBetween
 
 `.isBetween` para verificar se uma data está entre duas outras datas
diff --git a/docs/pt-br/Plugin.md b/docs/pt-br/Plugin.md
index e67e1bb04..17a11721e 100644
--- a/docs/pt-br/Plugin.md
+++ b/docs/pt-br/Plugin.md
@@ -155,6 +155,28 @@ dayjs.extend(weekOfYear)
 dayjs('06/27/2018').week() // 26
 ```
 
+### IsSameOrAfter
+ - IsSameOrAfter adds `.isSameOrAfter()` API to returns a `boolean` indicating if a date is same of after another date.
+
+```javascript
+import isSameOrAfter from 'dayjs/plugin/isSameOrAfter'
+
+dayjs.extend(isSameOrAfter)
+
+dayjs('2010-10-20').isSameOrAfter('2010-10-19', 'year');
+```
+
+### IsSameOrBefore
+ - IsSameOrBefore adds `.isSameOrBefore()` API to returns a `boolean` indicating if a date is same of before another date.
+
+```javascript
+import isSameOrBefore from 'dayjs/plugin/isSameOrBefore'
+
+dayjs.extend(isSameOrBefore)
+
+dayjs('2010-10-20').isSameOrBefore('2010-10-19', 'year');
+```
+
 ### IsBetween
  - IsBetween adiciona `.isBetween()` à API para retornar um `boolean` indicando se a data está entre outras duas datas.
 
@@ -163,7 +185,7 @@ import isBetween from 'dayjs/plugin/isBetween'
 
 dayjs.extend(isBetween)
 
-dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25')); // true
+dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25'), 'year');
 ```
 
 ## Customizar
diff --git a/docs/zh-cn/API-reference.md b/docs/zh-cn/API-reference.md
index b590055a9..93100de5e 100644
--- a/docs/zh-cn/API-reference.md
+++ b/docs/zh-cn/API-reference.md
@@ -48,7 +48,9 @@
   * [相对时间](#relativetime)
   * [是否是闰年](#是否是闰年)
   * [年中的第几周](#年中的第几周)
-  * [是否之间](#isbetween)
+  * [是否相同或之后](#是否相同或之后)
+  * [是否相同或之前](#是否相同或之前)
+  * [是否之间](#是否之间)
 
 ---
 如果没有特别说明，Day.js 的返回值都是新的 `Dayjs` 对象。
@@ -338,24 +340,27 @@ dayjs().toString();
 
 检查一个 `Dayjs` 对象是否在另一个 `Dayjs` 对象时间之前。
 ```js
-dayjs().isBefore(Dayjs);
+dayjs().isBefore(Dayjs, unit? : String);
 dayjs().isBefore(dayjs()); // false
+dayjs().isBefore(dayjs(), 'year'); // false
 ```
 #### 是否相同
 - return Boolean
 
 检查一个 `Dayjs` 对象是否和另一个 `Dayjs` 对象时间相同。
 ```js
-dayjs().isSame(Dayjs);
+dayjs().isSame(Dayjs, unit? : String);
 dayjs().isSame(dayjs()); // true
+dayjs().isSame(dayjs(), 'year'); // true
 ```
 #### 是否之后
 - return Boolean
 
 检查一个 `Dayjs` 对象是否在另一个 `Dayjs` 对象时间之后。
 ```js
-dayjs().isAfter(Dayjs);
+dayjs().isAfter(Dayjs, unit? : String);
 dayjs().isAfter(dayjs()); // false
+dayjs().isAfter(dayjs(), 'year'); // false
 ```
 
 ### 是否是 Dayjs `.isDayjs(compared: any)`
@@ -387,6 +392,18 @@ dayjs.isDayjs(new Date()); // false
 
 插件 [`WeekOfYear`](./Plugin.md#weekofyear)
 
+### 是否相同或之后
+
+`.isSameOrAfter` 返回一个时间和一个时间相同或在一个时间之后
+
+plugin [`IsSameOrAfter`](./Plugin.md#issameorafter)
+
+### 是否相同或之前
+
+`.isSameOrBefore` 返回一个时间是否和一个时间相同或在一个时间之前
+
+plugin [`IsSameOrBefore`](./Plugin.md#issameorbefore)
+
 ### 是否之间
 
 `.isBetween` 返回一个时间是否介于两个时间之间
diff --git a/docs/zh-cn/Plugin.md b/docs/zh-cn/Plugin.md
index 5d88c44b6..082dd6562 100644
--- a/docs/zh-cn/Plugin.md
+++ b/docs/zh-cn/Plugin.md
@@ -144,7 +144,7 @@ List of added formats:
 | `BBBB` | 2561             | Full BE Year (Year + 543)             |
 | `BB`   | 61               | 2-digit of BE Year                    |
 
-### 年中的第几周
+### WeekOfYear
  - WeekOfYear 增加了 `.week()` API 返回一个 `number` 来表示 `Dayjs` 的日期是年中第几周.
 
 ```javascript
@@ -155,6 +155,28 @@ dayjs.extend(weekOfYear)
 dayjs('06/27/2018').week() // 26
 ```
 
+### IsSameOrAfter
+ - IsSameOrAfter 增加了 `.isSameOrAfter()` API 返回一个 `boolean` 来展示一个时间是否和一个时间相同或在一个时间之后.
+
+```javascript
+import isSameOrAfter from 'dayjs/plugin/isSameOrAfter'
+
+dayjs.extend(isSameOrAfter)
+
+dayjs('2010-10-20').isSameOrAfter('2010-10-19', 'year');
+```
+
+### IsSameOrBefore
+ - IsSameOrBefore 增加了 `.isSameOrBefore()` API 返回一个 `boolean` 来展示一个时间是否和一个时间相同或在一个时间之前.
+
+```javascript
+import isSameOrBefore from 'dayjs/plugin/isSameOrBefore'
+
+dayjs.extend(isSameOrBefore)
+
+dayjs('2010-10-20').isSameOrBefore('2010-10-19', 'year');
+```
+
 ### IsBetween
  - IsBetween 增加了 `.isBetween()` API 返回一个 `boolean` 来展示一个时间是否介于两个时间之间.
 
@@ -163,7 +185,7 @@ import isBetween from 'dayjs/plugin/isBetween'
 
 dayjs.extend(isBetween)
 
-dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25')); // true
+dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25'), 'year');
 ```
 
 ## 自定义
diff --git a/src/index.js b/src/index.js
index 3b57655bc..b4875227e 100644
--- a/src/index.js
+++ b/src/index.js
@@ -244,7 +244,7 @@ class Dayjs {
       [C.MIN]: C.MILLISECONDS_A_MINUTE,
       [C.H]: C.MILLISECONDS_A_HOUR,
       [C.S]: C.MILLISECONDS_A_SECOND
-    }[unit] || 1
+    }[unit] || 1 // ms
 
     const nextTimeStamp = this.valueOf() + (number * step)
     return wrapper(nextTimeStamp, this)
@@ -296,7 +296,7 @@ class Dayjs {
         ss: Utils.padStart(this.$s, 2, '0'),
         SSS: Utils.padStart(this.$ms, 3, '0'),
         Z: zoneStr
-      }[match] || zoneStr.replace(':', '')
+      }[match] || zoneStr.replace(':', '') // 'ZZ'
     })
   }
 
@@ -315,7 +315,7 @@ class Dayjs {
       [C.H]: diff / C.MILLISECONDS_A_HOUR,
       [C.MIN]: diff / C.MILLISECONDS_A_MINUTE,
       [C.S]: diff / C.MILLISECONDS_A_SECOND
-    }[unit] || diff
+    }[unit] || diff // milliseconds
 
     return float ? result : Utils.absFloor(result)
   }
diff --git a/test/query.test.js b/test/query.test.js
index 09f99b7f8..2c05ec96d 100644
--- a/test/query.test.js
+++ b/test/query.test.js
@@ -1,4 +1,3 @@
-import moment from 'moment'
 import MockDate from 'mockdate'
 import dayjs from '../src'
 
@@ -10,40 +9,33 @@ afterEach(() => {
   MockDate.reset()
 })
 
-const testArr = [dayjs, moment]
 
 describe('Is Before Is After Is Same', () => {
   it('Compare to dayjs object', () => {
-    testArr.forEach((instance) => {
-      const dayA = instance()
-      const dayB = dayA.clone().add(1, 'day')
-      const dayC = dayA.clone().subtract(1, 'day')
-      expect(dayC.isBefore(dayA)).toBe(true)
-      expect(dayA.isSame(instance())).toBe(true)
-      expect(dayB.isAfter(dayA)).toBe(true)
-      expect(dayA.isSame()).toBe(true)
-      expect(dayB.isAfter()).toBe(true)
-      expect(dayC.isBefore()).toBe(true)
-    })
+    const dayA = dayjs()
+    const dayB = dayA.clone().add(1, 'day')
+    const dayC = dayA.clone().subtract(1, 'day')
+    expect(dayC.isBefore(dayA)).toBe(true)
+    expect(dayA.isSame(dayjs())).toBe(true)
+    expect(dayB.isAfter(dayA)).toBe(true)
+    expect(dayA.isSame()).toBe(true)
+    expect(dayB.isAfter()).toBe(true)
+    expect(dayC.isBefore()).toBe(true)
   })
 
   it('No value', () => {
-    testArr.forEach((instance) => {
-      const dayA = instance()
-      const dayB = dayA.clone().add(1, 'day')
-      const dayC = dayA.clone().subtract(1, 'day')
-      expect(dayA.isSame()).toBe(true)
-      expect(dayB.isAfter()).toBe(true)
-      expect(dayC.isBefore()).toBe(true)
-    })
+    const dayA = dayjs()
+    const dayB = dayA.clone().add(1, 'day')
+    const dayC = dayA.clone().subtract(1, 'day')
+    expect(dayA.isSame()).toBe(true)
+    expect(dayB.isAfter()).toBe(true)
+    expect(dayC.isBefore()).toBe(true)
   })
 
   it('With string', () => {
-    testArr.forEach((instance) => {
-      const dayD = instance()
-      expect(dayD.isSame('20180101')).toBe(false)
-      expect(dayD.isAfter('20180101')).toBe(true)
-      expect(dayD.isBefore('20180101')).toBe(false)
-    })
+    const dayD = dayjs()
+    expect(dayD.isSame('20180101')).toBe(false)
+    expect(dayD.isAfter('20180101')).toBe(true)
+    expect(dayD.isBefore('20180101')).toBe(false)
   })
 })