Add asMatching

README.md

@@ -133,6 +133,18 @@ asBoolean('boo') // FAIL (not a boolean)
 asBoolean(123) // FAIL (not a boolean)
 ```
 
+### `asMatching`
+
+This higher-order sanitizer accepts values that are strings matching the regex provided as an argument. You can pass a custom message to it.
+
+```javascript
+const sanitizer = asMatching(/aaa/, 'custom message')
+
+sanitizer('aaa') // OK 'aaa'
+sanitizer(123) // FAIL (custom message)
+sanitizer('b') // FAIL (custom message)
+```
+
 ### `asObject`
 
 This higher-order sanitizer requires a schema in the form of an object. Values of the schema are sanitizers used to sanitize the values of the input. Returns an object with keys and values matching the schema.

package.json

@@ -1,10 +1,10 @@
 {
   "name": "@restless/restless",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "author": "Piotr Szlachciak <[email protected]>",
   "description": "Express.js api, validations and more",
   "keywords": [
-    "express",  
+    "express",
     "rest",
     "api",
     "validation",

src/index.ts

@@ -9,3 +9,4 @@ export { asObject } from './sanitize/asObject'
 export { asArray } from './sanitize/asArray'
 export { asOptional } from './sanitize/asOptional'
 export { asChecked } from './sanitize/asChecked'
+export { asMatching } from './sanitize/asMatching'

src/sanitize/asMatching.ts

@@ -0,0 +1,6 @@
+import { Either, Sanitizer } from './sanitizer'
+
+export const asMatching = (re: RegExp, message?: string): Sanitizer<string> =>
+  (value, path) => typeof value === 'string' && re.test(value)
+    ? Either.right(value)
+    : Either.left([{ path, expected: message || `string matching ${re}` }])

src/sanitize/asString.ts

@@ -1,6 +1,6 @@
 import { Either, Sanitizer } from './sanitizer'
 
-export const asString: Sanitizer<string> = (value, path) => {
-  if (typeof value === 'string') return Either.right(value)
-  else return Either.left([{ path, expected: 'string' }])
-}
+export const asString: Sanitizer<string> = (value, path) =>
+  typeof value === 'string'
+    ? Either.right(value)
+    : Either.left([{ path, expected: 'string' }])

test/sanitize/asMatching.test.ts

@@ -0,0 +1,35 @@
+import { expect } from 'chai'
+import { Either } from '../../src/sanitize/sanitizer'
+import { asMatching } from '../../src/sanitize/asMatching'
+
+describe('asString', () => {
+  it('sanitizes strings', async () => {
+    const asMyString = asMatching(/.*/)
+    const result = asMyString('hello', '')
+    expect(result).to.deep.equal(Either.right('hello'))
+  })
+
+  it('does not accept non-strings', async () => {
+    const asMyString = asMatching(/.*/)
+    const result = asMyString(123, 'path')
+    expect(result).to.deep.equal(
+      Either.left([{ path: 'path', expected: 'string matching /.*/' }])
+    )
+  })
+
+  it('checks the regex', async () => {
+    const asMyString = asMatching(/^a?b$/)
+    const result = asMyString('ac', 'path')
+    expect(result).to.deep.equal(
+      Either.left([{ path: 'path', expected: 'string matching /^a?b$/' }])
+    )
+  })
+
+  it('accepts a custom message', async () => {
+    const asMyString = asMatching(/^a?b$/, 'foo')
+    const result = asMyString('ac', 'path')
+    expect(result).to.deep.equal(
+      Either.left([{ path: 'path', expected: 'foo' }])
+    )
+  })
+})