diff --git a/test/plugin/isBetween.d.test.ts b/test/plugin/isBetween.d.test.ts
new file mode 100644
index 000000000..4542e4b61
--- /dev/null
+++ b/test/plugin/isBetween.d.test.ts
@@ -0,0 +1,6 @@
+import * as dayjs from 'dayjs'
+import * as isBetween from 'dayjs/plugin/isBetween'
+
+dayjs.extend(isBetween)
+
+dayjs('2010-10-20').isBetween('2010-10-19', dayjs('2010-10-25')) === true
diff --git a/test/plugin/isLeapYear.d.test.ts b/test/plugin/isLeapYear.d.test.ts
new file mode 100644
index 000000000..399930658
--- /dev/null
+++ b/test/plugin/isLeapYear.d.test.ts
@@ -0,0 +1,6 @@
+import * as dayjs from 'dayjs'
+import * as isLeapYear from 'dayjs/plugin/isLeapYear'
+
+dayjs.extend(isLeapYear)
+
+dayjs('2010-10-20').isLeapYear() === false
diff --git a/test/plugin/relativeTime.d.test.ts b/test/plugin/relativeTime.d.test.ts
new file mode 100644
index 000000000..1124553f0
--- /dev/null
+++ b/test/plugin/relativeTime.d.test.ts
@@ -0,0 +1,20 @@
+import * as dayjs from 'dayjs'
+import * as relativeTime from 'dayjs/plugin/relativeTime'
+
+dayjs.extend(relativeTime)
+
+dayjs().fromNow().trim()
+dayjs().fromNow(true).trim()
+
+dayjs().from(dayjs()).trim()
+dayjs().from(123, true).trim()
+dayjs().from('2018-01-23').trim()
+dayjs().from(new Date(), true).trim()
+
+dayjs().toNow().trim()
+dayjs().toNow(true).trim()
+
+dayjs().to(dayjs()).trim()
+dayjs().to(123, true).trim()
+dayjs().to('2018-01-23').trim()
+dayjs().to(new Date(), true).trim()
diff --git a/test/plugin/weekOfYear.d.test.ts b/test/plugin/weekOfYear.d.test.ts
new file mode 100644
index 000000000..bfaceede9
--- /dev/null
+++ b/test/plugin/weekOfYear.d.test.ts
@@ -0,0 +1,6 @@
+import * as dayjs from 'dayjs'
+import * as weekOfYear from 'dayjs/plugin/weekOfYear'
+
+dayjs.extend(weekOfYear)
+
+dayjs('2010-10-20').week() === 43
diff --git a/types/plugin/advancedFormat.d.ts b/types/plugin/advancedFormat.d.ts
new file mode 100644
index 000000000..30ec75e5d
--- /dev/null
+++ b/types/plugin/advancedFormat.d.ts
@@ -0,0 +1,4 @@
+import { PluginFunc } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
diff --git a/types/plugin/buddhistEra.d.ts b/types/plugin/buddhistEra.d.ts
new file mode 100644
index 000000000..30ec75e5d
--- /dev/null
+++ b/types/plugin/buddhistEra.d.ts
@@ -0,0 +1,4 @@
+import { PluginFunc } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
diff --git a/types/plugin/isBetween.d.ts b/types/plugin/isBetween.d.ts
new file mode 100644
index 000000000..41afb64cf
--- /dev/null
+++ b/types/plugin/isBetween.d.ts
@@ -0,0 +1,10 @@
+import { PluginFunc, DateType } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
+
+declare module 'dayjs' {
+  interface Dayjs {
+    isBetween(a: DateType, b: DateType): boolean
+  }
+}
diff --git a/types/plugin/isLeapYear.d.ts b/types/plugin/isLeapYear.d.ts
new file mode 100644
index 000000000..5be74092b
--- /dev/null
+++ b/types/plugin/isLeapYear.d.ts
@@ -0,0 +1,10 @@
+import { PluginFunc } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
+
+declare module 'dayjs' {
+  interface Dayjs {
+    isLeapYear(): boolean
+  }
+}
diff --git a/types/plugin/relativeTime.d.ts b/types/plugin/relativeTime.d.ts
new file mode 100644
index 000000000..306493002
--- /dev/null
+++ b/types/plugin/relativeTime.d.ts
@@ -0,0 +1,13 @@
+import { PluginFunc, DateType } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
+
+declare module 'dayjs' {
+  interface Dayjs {
+    fromNow(withoutSuffix?: boolean): string
+    from(compared: DateType, withoutSuffix?: boolean): string
+    toNow(withoutSuffix?: boolean): string
+    to(compared: DateType, withoutSuffix?: boolean): string
+  }
+}
diff --git a/types/plugin/weekOfYear.d.ts b/types/plugin/weekOfYear.d.ts
new file mode 100644
index 000000000..360219556
--- /dev/null
+++ b/types/plugin/weekOfYear.d.ts
@@ -0,0 +1,10 @@
+import { PluginFunc } from 'dayjs'
+
+declare const plugin: PluginFunc
+export = plugin
+
+declare module 'dayjs' {
+  interface Dayjs {
+    week(): number
+  }
+}