Add slice method (#6)

README.md

@@ -22,6 +22,9 @@ ssv.add('mark travis', 'matt') // 'mark travis matt'
 ssv.add('mark travis', 'travis') // 'mark travis'
 ssv.push('mark travis', 'travis') // 'mark travis travis'
 ssv.pop('mark travis tom') // 'tom'
+ssv.slice('travis mark tom', 1) // 'mark tom'
+ssv.slice('travis mark tom', -1) // 'tom'
+ssv.slice(' travis mark tom', 0, 1) // 'travis'
 ssv.concat('mark tom', 'travis matt') // 'mark tom travis matt'
 ssv.concat(' mark  tom ', ' travis  matt ') // 'mark tom travis matt'
 ssv.compact('  mark   travis   matt ') // 'mark travis matt'
@@ -48,6 +51,9 @@ Add <var>value</var> to <var>SSV</var> string whether unique or not
 ### ssv.pop(SSV, value)
 Get last SSV value
 
+### ssv.slice(SSV, begin, end)
+Slice SSV values per `[].slice`
+
 ### ssv.compact(SSV)
 Normalize <var>SSV</var> string to a trim compact string
 

ssv.d.ts

@@ -8,6 +8,7 @@ declare module ssv {
   export function concat(ssv: string, more: string): string;
   export function parse(ssv: string): string[];
   export function split(ssv: string): string[];
+  export function slice(ssv: string, begin?: number, end?: number): string;
 }
 
 declare module "ssv" {

ssv.js

@@ -2,6 +2,7 @@
   typeof module != 'undefined' && module.exports ? module.exports = make() : root[name] = make()
 }(this, 'ssv', function() {
 
+  var vacant
   var api = {}
   var word = /\S+/g
   var space = ' '
@@ -32,6 +33,13 @@
     return compact(ssv + space + more)
   }
 
+  function slice(ssv, begin, end) {
+    ssv = split(ssv)
+    if (vacant === begin) begin = 0
+    if (vacant === end) end = ssv.length
+    return ssv.slice(begin, end).join(space)
+  }
+
   function push(ssv, value) {
     ssv = split(ssv)
     ssv.push(value)
@@ -55,5 +63,6 @@
   api['push'] = push
   api['add'] = add
   api['remove'] = remove
+  api['slice'] = slice
   return api
 });

test.js

@@ -28,6 +28,19 @@
   expect(api.has('  yes   no  ', 'yes'), true)
   console.log('#has tests passed')
 
+  expect(api.slice(''), '')
+  expect(api.slice('', 5), '')
+  expect(api.slice('', -1), '')
+  expect(api.slice('zed one two', 0), 'zed one two')
+  expect(api.slice('zed one two', -2), 'one two')
+  expect(api.slice('zed one two', 0, 1), 'zed')
+  expect(api.slice('zed one two', 1, 2), 'one')
+  expect(api.slice('zed one two', 1, 3), 'one two')
+  expect(api.slice('zed one two', 0, -2), 'zed')
+  expect(api.slice('zed one two', 0, -1), 'zed one')
+  expect(api.slice('zed one two', 1, -1), 'one')
+  console.log('#slice tests passed')
+
   expect(api.pop(''), '')
   expect(api.pop('yes'), 'yes')
   expect(api.pop('yes no'), 'no')