feat: implement Math.abs pipe (#64)

Author: baso10

docs/math.md

@@ -9,6 +9,7 @@
 * [`random`](#random)
 * [`pow`](#pow)
 * [`sqrt`](#sqrt)
+* [`abs`](#abs)
 
 You can check the module import [`here`](./modules.md).
 
@@ -188,3 +189,19 @@ import { PowPipe } from 'angular-pipes';
 {{ 2 | pow }} <!-- 4 -->
 {{ 2 | pow: 3 }} <!-- 8 -->
 ```
+
+#### abs
+
+Returns the absolute of a number.
+
+##### File
+
+```typescript
+import { AbsPipe } from 'angular-pipes';
+```
+
+##### Usage
+
+```html
+{{ -2 | abs }} <!-- 2 -->
+```

src/math/abs.pipe.spec.ts

@@ -0,0 +1,27 @@
+import { AbsPipe } from './abs.pipe';
+        
+
+
+describe('AbsPipe', () => {
+    
+    let pipe: AbsPipe;
+    
+    beforeEach(() => {
+       pipe = new AbsPipe(); 
+    });
+    
+    it('Should return 2', () => {
+        
+        expect(pipe.transform(2)).toEqual(2);
+    });
+    
+    it('Should return 2', () => {
+       
+        expect(pipe.transform(-2)).toEqual(2); 
+    });
+
+    it('Should return NaN', () => {
+        expect(pipe.transform('a')).toEqual('NaN');
+    });
+  
+});

src/math/abs.pipe.ts

@@ -0,0 +1,17 @@
+import { Pipe, PipeTransform  } from '@angular/core';
+import { isNumberFinite } from '../utils/utils';
+
+@Pipe({
+  name: 'abs'
+})
+export class AbsPipe implements PipeTransform {
+  
+  transform (input: any): any {
+    
+    if (!isNumberFinite(input)) {
+      return 'NaN';
+    }
+    
+    return Math.abs(input);
+  }
+}

src/math/math.module.ts

@@ -9,6 +9,7 @@ import { RadiansPipe } from './radians.pipe';
 import { RandomPipe } from './random.pipe';
 import { SqrtPipe } from './sqrt.pipe';
 import { PowPipe } from './pow.pipe';
+import { AbsPipe } from './abs.pipe';
 
 @NgModule({
   declarations: [
@@ -20,7 +21,8 @@ import { PowPipe } from './pow.pipe';
     RadiansPipe,
     RandomPipe,
     SqrtPipe,
-    PowPipe
+    PowPipe,
+	AbsPipe
   ],
   exports: [
     BytesPipe,
@@ -31,7 +33,8 @@ import { PowPipe } from './pow.pipe';
     RadiansPipe,
     RandomPipe,
     SqrtPipe,
-    PowPipe
+    PowPipe,
+	AbsPipe
   ]
 })
 export class NgMathPipesModule {}

src/public_api.ts

@@ -78,6 +78,7 @@ export { RadiansPipe } from './math/radians.pipe';
 export { RandomPipe } from './math/random.pipe';
 export { SqrtPipe } from './math/sqrt.pipe';
 export { PowPipe } from './math/pow.pipe';
+export { AbsPipe } from './math/abs.pipe';
 
 export { KeysPipe } from './object/keys.pipe';
 export { ToArrayPipe } from './object/to-array.pipe';