feat (pipe): Add new pipe - 'SnakeCasePipe'

Author: rafaelss95

src/string/index.ts

@@ -8,6 +8,7 @@ import {PhonePipe} from './phone.pipe';
 import {RepeatPipe} from './repeat.pipe';
 import {RightTrimPipe} from './rtrim.pipe';
 import {SlugifyPipe} from './slugify.pipe';
+import {SnakeCasePipe} from './snake-case.pipe';
 import {SplitPipe} from './split.pipe';
 import {StartsWithPipe} from './starts-with.pipe';
 import {StringularPipe} from './stringular.pipe';
@@ -29,6 +30,7 @@ export * from './phone.pipe';
 export * from './repeat.pipe';
 export * from './rtrim.pipe';
 export * from './slugify.pipe';
+export * from './snake-case.pipe';
 export * from './split.pipe';
 export * from './starts-with.pipe';
 export * from './stringular.pipe';
@@ -44,22 +46,16 @@ export * from './wrap.pipe';
 
 @NgModule({
   declarations: [
-    EndsWithPipe,   LatinizePipe,   LeftTrimPipe,
-    MatchPipe,      PhonePipe,      RepeatPipe,
-    RightTrimPipe,  SlugifyPipe,    SplitPipe,
-    StartsWithPipe, StringularPipe, StripTagsPipe,
-    TestPipe,       TitleizePipe,   TrimPipe,
-    TruncatePipe,   UcfirstPipe,    UriComponentEncodePipe,
-    UriEncodePipe,  WrapPipe
+    EndsWithPipe,           LatinizePipe,  LeftTrimPipe,  MatchPipe, PhonePipe,      RepeatPipe,
+    RightTrimPipe,          SlugifyPipe,   SnakeCasePipe, SplitPipe, StartsWithPipe, StringularPipe,
+    StripTagsPipe,          TestPipe,      TitleizePipe,  TrimPipe,  TruncatePipe,   UcfirstPipe,
+    UriComponentEncodePipe, UriEncodePipe, WrapPipe
   ],
   exports: [
-    EndsWithPipe,   LatinizePipe,   LeftTrimPipe,
-    MatchPipe,      PhonePipe,      RepeatPipe,
-    RightTrimPipe,  SlugifyPipe,    SplitPipe,
-    StartsWithPipe, StringularPipe, StripTagsPipe,
-    TestPipe,       TitleizePipe,   TrimPipe,
-    TruncatePipe,   UcfirstPipe,    UriComponentEncodePipe,
-    UriEncodePipe,  WrapPipe
+    EndsWithPipe,           LatinizePipe,  LeftTrimPipe,  MatchPipe, PhonePipe,      RepeatPipe,
+    RightTrimPipe,          SlugifyPipe,   SnakeCasePipe, SplitPipe, StartsWithPipe, StringularPipe,
+    StripTagsPipe,          TestPipe,      TitleizePipe,  TrimPipe,  TruncatePipe,   UcfirstPipe,
+    UriComponentEncodePipe, UriEncodePipe, WrapPipe
   ]
 })
 export class StringPipesModule {

src/string/phone.pipe.ts

@@ -1,19 +1,19 @@
 import {Pipe, PipeTransform} from '@angular/core';
 
-import {getPhone, IsNil} from '../utils/utils';
+import {getPhone, isNil} from '../utils/utils';
 
 @Pipe({name: 'phone'})
 export class PhonePipe implements PipeTransform {
   transform(input: string, locale: string = 'en-US', showCountryCode: boolean = false): string {
-    if (IsNil(input) || !/^[a-zA-Z]{2}-[a-zA-Z]{2}$/.test(locale)) return input;
+    if (isNil(input) || !/^[a-zA-Z]{2}-[a-zA-Z]{2}$/.test(locale)) return input;
 
     const strInput: string = input.replace(/[^0-9]/g, '');
     const splittedLocale = locale.split('-');
     const formattedLocale: string =
         `${splittedLocale[0].toLowerCase()}-${splittedLocale[1].toUpperCase()}`;
     const phoneObj: any = getPhone(formattedLocale);
 
-    if (IsNil(phoneObj) || strInput.length < phoneObj.minLength) return input;
+    if (isNil(phoneObj) || strInput.length < phoneObj.minLength) return input;
 
     const pattern: RegExp = phoneObj.pattern;
     const matches: Array<string> = strInput.match(pattern);

src/string/snake-case.pipe.ts

@@ -0,0 +1,16 @@
+import {Pipe, PipeTransform} from '@angular/core';
+
+import {isString} from '../utils/utils';
+
+@Pipe({name: 'snakeCase'})
+export class SnakeCasePipe implements PipeTransform {
+  transform(input: string): string {
+    if (!isString(input)) return input;
+
+    return input.trim()
+        .replace(/\s+/g, '')
+        .replace(
+            /[A-Z]/g,
+            (value, index) => index === 0 ? value.toLowerCase() : `_${value.toLowerCase()}`);
+  }
+}

src/utils/utils.ts

@@ -2,7 +2,7 @@ export const isArray = (value: any): boolean => Array.isArray(value);
 
 export const isFunction = (value: any): boolean => typeof value === 'function';
 
-export const IsNil = (value: any): boolean => value === null || typeof value === 'undefined';
+export const isNil = (value: any): boolean => value === null || typeof value === 'undefined';
 
 export const isNull = (value: any): boolean => value === null;
 

test/string/snake-case.pipe.spec.ts

@@ -0,0 +1,43 @@
+import {SnakeCasePipe} from '../../src/index';
+
+describe('SnakeCasePipe', () => {
+  let pipe: SnakeCasePipe;
+
+  beforeEach(() => {
+    pipe = new SnakeCasePipe();
+  });
+
+  const data: Array<any> = [
+    {'value': 'ASimpleWord', 'toEqual': 'a_simple_word', 'valid': true},
+    {'value': 'aMediumWordHere', 'toEqual': 'a_medium_word_here', 'valid': true}, {
+      'value': 'ANUPPERCASEDWORDHERE',
+      'toEqual': 'a_n_u_p_p_e_r_c_a_s_e_d_w_o_r_d_h_e_r_e',
+      'valid': true
+    },
+    {'value': 'alowercasedword', 'toEqual': 'alowercasedword', 'valid': true},
+    {'value': '     ', 'toEqual': '', 'valid': true},
+    {'value': '  SOME WHITE SPACES  ', 'toEqual': 's_o_m_e_w_h_i_t_e_s_p_a_c_e_s', 'valid': true},
+    {'value': null, 'toEqual': 'a_simple_word', 'valid': false},
+    {'value': undefined, 'toEqual': 'a_medium_word_here', 'valid': false}, {
+      'value': 'ANUPPERCASEDWORDHERe',
+      'toEqual': 'a_n_u_p_p_e_r_c_a_s_e_d_w_o_r_d_h_e_r_e',
+      'valid': false
+    },
+    {'value': 'aloweRcasedword', 'toEqual': 'alowercasedword', 'valid': false}
+  ];
+
+  for (const element of data) {
+    const testCase = `${element.value} should be ${element.valid ? 'equal' :
+                                                                   'not equal'
+                                                                   } to ${element.toEqual}`;
+
+    it(testCase, () => {
+      if (element.valid) {
+        expect(pipe.transform(element.value)).toEqual(element.toEqual);
+      } else {
+        expect(pipe.transform(element.value)).not.toEqual(element.toEqual);
+      }
+    })
+  }
+
+});

test/string/test.pipe.spec.ts

@@ -8,14 +8,14 @@ describe('TestPipe', () => {
   });
 
   it('should test a string with given pattern', () => {
-    expect(pipe.transform('15/12/2003', '^[0-9]{2}[/]{1}[0-9]{2}[/]{1}[0-9]{4}$', 'i')).toBeTruthy();
+    expect(pipe.transform('15/12/2003', '^[0-9]{2}[/]{1}[0-9]{2}[/]{1}[0-9]{4}$', 'i'))
+        .toBeTruthy();
     expect(pipe.transform('foobarbaz', '^[a-z]{3,}$')).toBeTruthy();
     expect(pipe.transform('FOOBARBAZ', '^[a-z]{3,}$', 'i')).toBeTruthy();
     expect(pipe.transform('FOOBARBAZ', '^[a-z]{3,}$')).toBeFalsy();
     expect(pipe.transform('foobarbaz', '\\W')).toBeFalsy();
     expect(pipe.transform('foobarbaz', '\\w')).toBeTruthy();
-    expect(pipe.transform('1a/bb/2003', '^[0-9]{2}[/]{1}[0-9]{2}[/]{1}[0-9]{4}$', 'i'))
-        .toBeFalsy();
+    expect(pipe.transform('1a/bb/2003', '^[0-9]{2}[/]{1}[0-9]{2}[/]{1}[0-9]{4}$', 'i')).toBeFalsy();
   });
 
 });