feat(validation): add decimal rule

lib/validation/rules/decimal.ts

@@ -0,0 +1,8 @@
+import { decimal as baseDecimal, helpers } from '@vuelidate/validators'
+
+export function decimal(msg?: string) {
+  return helpers.withMessage(
+    () => msg ?? 'The value must be valid decimal numbers.',
+    baseDecimal
+  )
+}

lib/validation/rules/index.ts

@@ -13,6 +13,7 @@ export * from './requiredHms'
 export * from './requiredIf'
 export * from './requiredYmd'
 export * from './url'
+export * from './decimal'
 export * from './month'
 export * from './ymd'
 export * from './rule'

tests/validation/rules/decimal.spec.ts

@@ -0,0 +1,21 @@
+import { decimal } from 'sefirot/validation/rules'
+
+describe('validation/rules/decimal', () => {
+  test('it validates whether the value is decimal', () => {
+    const rule = decimal()
+    expect(rule.$validator(0, null, null)).toBe(true)
+    expect(rule.$validator(1, null, null)).toBe(true)
+    expect(rule.$validator(-1, null, null)).toBe(true)
+    expect(rule.$validator(1.1, null, null)).toBe(true)
+    expect(rule.$validator(-1.1, null, null)).toBe(true)
+    expect(rule.$validator('1.00', null, null)).toBe(true)
+    expect(rule.$validator('-1.00', null, null)).toBe(true)
+    expect(rule.$validator('abc', null, null)).toBe(false)
+    expect(rule.$validator(true, null, null)).toBe(false)
+  })
+
+  test('it can set custome error message', () => {
+    const rule = decimal('Custom message.')
+    expect(rule.$message({ $params: {} })).toBe('Custom message.')
+  })
+})