documentation updates.

README.md

@@ -49,13 +49,21 @@ tw.footer = '-footer';
 tw.wrap('body'); //=> header-body-footer
 ```
 
-See also: [grunt-file-wrap]
+For bulk file processing see [grunt-file-wrap].
 
 ## API
 
 ### wrap(text, [options]) ⇒ String
 
-Wraps the `text` with the current `header` + `footer`, according to the `options`, and returns the result. 
+Wraps the `text` with the current `header` + `footer`, according to the `options`, and returns the result.
+
+By default, the header is added when it is not found within the `text`, or when there are non-empty symbols that precede it.
+Accordingly, the footer is added when it is not found within the `text`, or when there are non-empty symbols that follow it. 
+
+Before the header or footer are searched for within `text`, they are trimmed first - all trailing empty symbols are removed
+from them (spaces, tabs, line breaks). However, their full content is used when adding them.
+
+Passing in a non-string value for the `text` will throw `Invalid text input.` 
 
 ##### options.skipCheck ⇒ Boolean
 
@@ -64,9 +72,6 @@ Disables verification for duplicate header or footer.
 * `false (default)` - add header + footer, if they are missing  
 * `true` - add header + footer regardless of their presence
 
-By default, the header is added when it is not found within the `text`, or when there are non-empty symbols that precede it.
-Accordingly, the footer is added when it is not found within the `text`, or when there are non-empty symbols that follow it. 
-
 Enabling this option is effectively switching off most of what this library does, which may be needed when processing
 files in a bulk requires no verification for certain file types.  
 
@@ -77,10 +82,6 @@ Enforces uniqueness of both header and footer within the `text`.
 * `false (default)` - verify for non-empty symbols that precede the header or follow the footer
 * `true` - ignore non-empty symbols, add header + footer only when not found
 
-By default, if the header is found within the `text`, it will still be added, if any non-empty symbol is found that precede
-the header - any symbol other than a space, a tab or a line break. Accordingly, the footer will be added even when it is
-found, if it is followed by any non-empty symbol.
-
 Enabling this option is to ignore non-empty symbols that precede the header or follow the footer, and add them only
 when they are not found within the `text` at all.
 
@@ -90,10 +91,14 @@ NOTE: This option has no effect when option `skipCheck` is enabled.
 
 Header text to be added, set to an empty string by default.
 
+Setting it to a non-string value will throw `Invalid header content.`
+
 ### wrap.footer ⇒ String
 
 Footer text to be added, set to an empty string by default.
 
+Setting it to a non-string value will throw `Invalid footer content.`
+
 ### wrap.clear()
 
 Resets content for both `header` and `footer` to empty strings.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "text-wrap",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "Fast and efficient way to wrap your text with a header + footer.",
   "main": "lib/index.js",
   "scripts": {