New Feature: add NonEmptyString, closes #13

gcanti · Nov 5, 2018 · ddf7953 · ddf7953
1 parent e0443b1
commit ddf7953
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diff --git a/src/NonEmptyString.ts b/src/NonEmptyString.ts
@@ -0,0 +1,8 @@
+import { Newtype, prism } from '.'
+import { Prism } from 'monocle-ts'
+
+export interface NonEmptyString extends Newtype<{ readonly NonEmptyString: unique symbol }, string> {}
+
+export const isNonEmptyString = (s: string) => s.length > 0
+
+export const prismNonEmptyString: Prism<string, NonEmptyString> = prism<NonEmptyString>(isNonEmptyString)
diff --git a/test/NontEmptyString.ts b/test/NontEmptyString.ts
@@ -0,0 +1,10 @@
+import * as assert from 'assert'
+import { none, some } from 'fp-ts/lib/Option'
+import { prismNonEmptyString } from '../src/NonEmptyString'
+
+describe('NonEmptyString', () => {
+  it('prismNonEmptyString', () => {
+    assert.deepEqual(prismNonEmptyString.getOption('a'), some('a'))
+    assert.deepEqual(prismNonEmptyString.getOption(''), none)
+  })
+})