Auto merge of #124 - martndemus:string-helper, r=poteto

Dry up string helpers

None

addon/-private/create-string-helper.js

@@ -0,0 +1,6 @@
+export default function(stringFunction) {
+  return function([string]) {
+    string = string || '';
+    return stringFunction(string);
+  }
+}

addon/helpers/camelize.js

@@ -1,9 +1,6 @@
 import { helper } from 'ember-helper';
 import { camelize as _camelize } from 'ember-string';
+import createStringHelperFunction from '../-private/create-string-helper';
 
-export function camelize([string]) {
-  string = string || '';
-  return _camelize(string);
-}
-
+export const camelize = createStringHelperFunction(_camelize);
 export default helper(camelize);

addon/helpers/capitalize.js

@@ -1,9 +1,6 @@
 import { helper } from 'ember-helper';
 import { capitalize as _capitalize } from 'ember-string';
+import createStringHelperFunction from '../-private/create-string-helper';
 
-export function capitalize([string]) {
-  string = string || '';
-  return _capitalize(string);
-}
-
+export const capitalize = createStringHelperFunction(_capitalize);
 export default helper(capitalize);

addon/helpers/classify.js

@@ -1,9 +1,6 @@
 import { helper } from 'ember-helper';
 import { classify as _classify } from 'ember-string';
+import createStringHelperFunction from '../-private/create-string-helper';
 
-export function classify([string]) {
-  string = string || '';
-  return _classify(string);
-}
-
+export const classify = createStringHelperFunction(_classify);
 export default helper(classify);

addon/helpers/dasherize.js

@@ -1,9 +1,6 @@
 import { helper } from 'ember-helper';
 import { dasherize as _dasherize } from 'ember-string';
+import createStringHelperFunction from '../-private/create-string-helper';
 
-export function dasherize([string]) {
-  string = string || '';
-  return _dasherize(string);
-}
-
+export const dasherize = createStringHelperFunction(_dasherize);
 export default helper(dasherize);

addon/helpers/underscore.js

@@ -1,9 +1,6 @@
 import { helper } from 'ember-helper';
 import { underscore as _underscore } from 'ember-string';
+import createStringHelperFunction from '../-private/create-string-helper';
 
-export function underscore([string]) {
-  string = string || '';
-  return _underscore(string);
-}
-
+export const underscore = createStringHelperFunction(_underscore);
 export default helper(underscore);