resolve(#41): Added convertCase

docs/functions.md

@@ -78,6 +78,17 @@ containsAll('This is my name', ['my', 'name']);
 
 // true
 ```
+
+### convertCase
+
+The `convertCase` function converts the given string to given mode:
+
+```js
+convertCase('HeLLo WoRLD', MB_CASE_LOWER);
+
+// 'hello world'
+```
+
 ### endsWith
 The `endsWith` function determines if the given string ends with the given value:
 ```js

docs/methods.md

@@ -124,6 +124,17 @@ Stringable.of('This is my name').containsAll(['my', 'name']);
 
 // true
 ```
+
+### convertCase
+
+The `convertCase` method converts the given string to given mode:
+
+```js
+Stringable.of('HeLLo WoRLD').convertCase(MB_CASE_LOWER);
+
+// 'hello world'
+```
+
 ### dirname
 The `dirname` method returns the parent directory portion of the given string:
 ```js

docs/statics.md

@@ -92,6 +92,17 @@ Str.containsAll('This is my name', ['my', 'name']);
 
 // true
 ```
+
+### convertCase
+
+The `convertCase` function converts the given string to given mode:
+
+```js
+Str.convertCase('HeLLo WoRLD', MB_CASE_LOWER);
+
+// 'hello world'
+```
+
 ### endsWith
 The `endsWith` function determines if the given string ends with the given value:
 ```js

src/Str.ts

@@ -9,6 +9,7 @@ import {
     charAt,
     contains,
     containsAll,
+    convertCase,
     endsWith,
     excerpt,
     explode,
@@ -107,6 +108,7 @@ export const Str = {
     },
     contains,
     containsAll,
+    convertCase,
     endsWith,
     excerpt,
     explode,

src/Stringable.ts

@@ -1,5 +1,6 @@
 import Str, {ExcerptOptions} from './Str';
 import {MarkdownConfiguration, defaultConfiguration} from './types/markdown';
+import {CASE_MODE, MB_CASE_FOLD} from './types/case';
 
 type Closure = Function | null | string | { (callback: Stringable, value: string): Stringable };
 
@@ -117,6 +118,12 @@ export class Stringable {
         return Str.containsAll(this._value, needles, ignoreCase);
     }
 
+    public convertCase = (mode: CASE_MODE = MB_CASE_FOLD): this => {
+        this._value = Str.convertCase(this._value, mode);
+
+        return this;
+    }
+
     public dirname = (levels: number = 1): this => {
         const components = this.explode('/', levels * -1);
 

src/methods.ts

@@ -1,3 +1,13 @@
+import {
+    CASE_MODE,
+    MB_CASE_FOLD, MB_CASE_FOLD_SIMPLE,
+    MB_CASE_LOWER,
+    MB_CASE_LOWER_SIMPLE,
+    MB_CASE_TITLE, MB_CASE_TITLE_SIMPLE,
+    MB_CASE_UPPER,
+    MB_CASE_UPPER_SIMPLE
+} from './types/case';
+
 export type ExcerptOptions = {
     radius?: number,
     omission?: string,
@@ -89,6 +99,22 @@ export const containsAll = (haystack: string, needles: string[], ignoreCase: boo
     return needles.every(needle => haystack.includes(needle));
 }
 
+export const convertCase = (string: string, mode: CASE_MODE = MB_CASE_FOLD): string => {
+    if ([MB_CASE_UPPER, MB_CASE_UPPER_SIMPLE].includes(mode)) {
+        return upper(string);
+    }
+
+    if ([MB_CASE_FOLD, MB_CASE_LOWER, MB_CASE_LOWER_SIMPLE, MB_CASE_FOLD_SIMPLE].includes(mode)) {
+        return lower(string);
+    }
+
+    if ([MB_CASE_TITLE, MB_CASE_TITLE_SIMPLE].includes(mode)) {
+        return title(string);
+    }
+
+    throw new Error(`Unsupported mode.`);
+}
+
 export const endsWith = (haystack: string, needles: null | string | number | string[]): boolean => {
     if (needles === null || needles === '') {
         return false;
@@ -99,7 +125,10 @@ export const endsWith = (haystack: string, needles: null | string | number | str
     return values.some(needle => haystack.endsWith(String(needle)));
 }
 
-export const excerpt = (text: string, phrase: string = '', {radius = 100, omission = '...'}: ExcerptOptions = {radius: 100, omission: '...'}): string => {
+export const excerpt = (text: string, phrase: string = '', {
+    radius = 100,
+    omission = '...'
+}: ExcerptOptions = {radius: 100, omission: '...'}): string => {
     if (text === phrase) {
         return text;
     }
@@ -394,7 +423,7 @@ export const parseCallback = (callback: string, method: string | null = null): A
         : [callback, method];
 }
 
-export const position = (haystack: string, needle: string, offset: number = 0): number|boolean => {
+export const position = (haystack: string, needle: string, offset: number = 0): number | boolean => {
     const index = haystack.indexOf(needle, offset);
 
     return index < 0 ? false : index;

src/types/case.ts

@@ -0,0 +1,10 @@
+export type CASE_MODE = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7;
+
+export const MB_CASE_UPPER = 0;
+export const MB_CASE_LOWER = 1;
+export const MB_CASE_TITLE = 2;
+export const MB_CASE_FOLD = 3;
+export const MB_CASE_UPPER_SIMPLE = 4;
+export const MB_CASE_LOWER_SIMPLE = 5;
+export const MB_CASE_TITLE_SIMPLE = 6;
+export const MB_CASE_FOLD_SIMPLE = 7;

tests/convertCase.test.js

@@ -0,0 +1,46 @@
+'use strict';
+
+const {Stringable} = require('../src/Stringable');
+const {Str} = require('../src/Str');
+const {convertCase} = require('../src/methods');
+const {MB_CASE_UPPER, MB_CASE_LOWER, MB_CASE_FOLD, MB_CASE_TITLE} = require('../src/types/case');
+
+it('converts the case of a string', () => {
+    expect(Stringable.of('hello').convertCase(MB_CASE_UPPER).toString())
+        .toBe('HELLO');
+
+    expect(Stringable.of('WORLD').convertCase(MB_CASE_UPPER).toString())
+        .toBe('WORLD');
+
+    expect(Stringable.of('HeLLo').convertCase(MB_CASE_LOWER).toString())
+        .toBe('hello');
+
+    expect(Stringable.of('WoRLD').convertCase(MB_CASE_LOWER).toString())
+        .toBe('world');
+
+    expect(Stringable.of('HeLLo WoRLD').convertCase(MB_CASE_TITLE).toString())
+        .toBe('Hello World');
+
+    expect(Stringable.of('HeLLo').convertCase(MB_CASE_FOLD).toString())
+        .toBe('hello');
+
+    expect(Stringable.of('WoRLD').convertCase(MB_CASE_FOLD).toString())
+        .toBe('world');
+
+    expect(Stringable.of('üöä').convertCase(MB_CASE_UPPER).toString())
+        .toBe('ÜÖÄ');
+
+    expect(Stringable.of('ÜÖÄ').convertCase(MB_CASE_LOWER).toString())
+        .toBe('üöä');
+
+    expect(Str.convertCase('hello', MB_CASE_UPPER).toString())
+        .toBe('HELLO');
+
+    expect(convertCase('hello', MB_CASE_UPPER).toString())
+        .toBe('HELLO');
+});
+
+it('returns error on unsupported mode', () => {
+    expect(() => Str.convertCase('Hello', -1).toString())
+        .toThrowError('Unsupported mode.');
+});