Add asInteger (#22)

sanitizers/README.md

@@ -24,6 +24,7 @@ yarn add @restless/sanitizers
 - [`cast`](#cast)
 - [`asString`](#asstring)
 - [`asNumber`](#assumber)
+- [`asInteger`](#asinteger)
 - [`asBoolean`](#asboolean)
 - [`asMatching`](#asmatching)
 - [`asObject`](#asobject)
@@ -64,6 +65,17 @@ asNumber('boo', 'path') // Result.error([{expected: 'number', path: 'path'}])
 asNumber({}, 'path') // Result.error([{expected: 'number', path: 'path'}])
 ```
 
+### `asInteger`
+
+Same as [`asNumber`](#asnumber), but does not accept floating point values.
+
+```javascript
+asInteger('123', 'path') // Result.ok(123)
+asInteger(0.2, 'path') // Result.error([{expected: 'integer', path: 'path'}])
+asInteger('boo', 'path') // Result.error([{expected: 'integer', path: 'path'}])
+asInteger({}, 'path') // Result.error([{expected: 'integer', path: 'path'}])
+```
+
 ### `asBoolean`
 
 Accepts any value that is a number or a string that represents a boolean (`"true"` or `"false"`). Returns a number.

sanitizers/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@restless/sanitizers",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "author": "Piotr Szlachciak <[email protected]>",
   "description": "Data sanitization in a functional way",
   "license": "Unlicense",

sanitizers/src/asInteger.ts

@@ -0,0 +1,10 @@
+import { asChecked } from './asChecked'
+import { asNumber } from './asNumber'
+import { withErrorMessage } from './withErrorMessage'
+
+const isInteger = (num: number) => num === Math.floor(num)
+
+export const asInteger = withErrorMessage(
+  asChecked(asNumber, isInteger),
+  'integer'
+)

sanitizers/src/index.ts

@@ -3,6 +3,7 @@ export { asArray } from './asArray'
 export { asBoolean } from './asBoolean'
 export { asChecked } from './asChecked'
 export { asFlatMapped } from './asFlatMapped'
+export { asInteger } from './asInteger'
 export { asMapped } from './asMapped'
 export { asMatching } from './asMatching'
 export { asNumber } from './asNumber'

sanitizers/test/asInteger.test.ts

@@ -0,0 +1,42 @@
+import { expect } from 'chai'
+import { asInteger, Result } from '../src'
+
+describe('asInteger', () => {
+  it('sanitizes strings containing integers', async () => {
+    const result = asInteger('-123', '')
+    expect(result).to.deep.equal(Result.ok(-123))
+  })
+
+  it('does not accept non-integer strings', async () => {
+    const result = asInteger('12abc', 'path')
+    expect(result).to.deep.equal(
+      Result.error([{ path: 'path', expected: 'integer' }])
+    )
+  })
+
+  it('sanitizes integers', async () => {
+    const result = asInteger(123, '')
+    expect(result).to.deep.equal(Result.ok(123))
+  })
+
+  it('does not accept floating point values', async () => {
+    const result = asInteger(123.45, 'path')
+    expect(result).to.deep.equal(
+      Result.error([{ path: 'path', expected: 'integer' }])
+    )
+  })
+
+  it('does not accept NaN', async () => {
+    const result = asInteger(NaN, 'path')
+    expect(result).to.deep.equal(
+      Result.error([{ path: 'path', expected: 'integer' }])
+    )
+  })
+
+  it('does not accept types other than integer or string', async () => {
+    const result = asInteger(true, 'path')
+    expect(result).to.deep.equal(
+      Result.error([{ path: 'path', expected: 'integer' }])
+    )
+  })
+})