feat: add pad

src/index.ts

@@ -55,6 +55,7 @@ export { default as mapValues } from './mapValues'
 export { default as noop } from './noop'
 export { default as objectToQueryString } from './objectToQueryString'
 export { default as omit } from './omit'
+export { default as pad } from './pad'
 export { default as padEnd } from './padEnd'
 export { default as padStart } from './padStart'
 export { default as parseCSSValue } from './parseCSSValue'

src/pad.ts

@@ -0,0 +1,22 @@
+import repeat from './repeat'
+
+/**
+ * 在 str 两侧填充字符。
+ *
+ * @param str 要填充的字符串
+ * @param [length=0] 目标长度
+ * @param [chars=' '] 填充字符
+ * @returns 填充后的字符串
+ */
+export default function pad(str: string, length: number = 0, chars: string = ' '): string {
+  let suffix = ''
+  let prefix = ''
+  if (length > str.length) {
+    const affixLength = length - str.length
+    const halfAffixLength = Math.floor(affixLength / 2)
+    const affix = repeat(chars, affixLength).slice(0, affixLength)
+    prefix = affix.substring(0, halfAffixLength)
+    suffix = affix.substring(halfAffixLength, affixLength)
+  }
+  return prefix + str + suffix
+}

src/padEnd.ts

@@ -12,7 +12,7 @@ export default function padEnd(str: string, length: number = 0, chars: string =
   let suffix = ''
   if (length > str.length) {
     const suffixLength = length - str.length
-    suffix = repeat(chars, length - str.length).slice(0, suffixLength)
+    suffix = repeat(chars, suffixLength).slice(0, suffixLength)
   }
   return str + suffix
 }

src/padStart.ts

@@ -12,7 +12,7 @@ export default function padStart(str: string, length: number = 0, chars: string
   let prefix = ''
   if (length > str.length) {
     const prefixLength = length - str.length
-    prefix = repeat(chars, length - str.length).slice(0, prefixLength)
+    prefix = repeat(chars, prefixLength).slice(0, prefixLength)
   }
   return prefix + str
 }

test/index.test.ts

@@ -1464,3 +1464,13 @@ describe('padEnd', () => {
     expect(vtils.padEnd('abc', 3)).toBe('abc')
   })
 })
+
+describe('pad', () => {
+  test('ok', () => {
+    expect(vtils.pad('1', 3, '0')).toBe('010')
+    expect(vtils.pad('1', 4, '0')).toBe('0100')
+    expect(vtils.pad('abc', 8)).toBe('  abc   ')
+    expect(vtils.pad('abc', 8, '_-')).toBe('_-abc_-_')
+    expect(vtils.pad('abc', 3)).toBe('abc')
+  })
+})