feat(api): Added check.found method, closes #48

README.md

@@ -96,6 +96,7 @@ for advice and examples.
   * [check.defend in module pattern](#checkdefend-in-module-pattern)
 * [Safe callback execution](#safe-callback-execution)
   * [check.then](#checkthen)
+  * [check.found](#checkfound)
   * [check.regexp](#checkregexp)
   * [check.promise](#checkpromise)
   * [check.validDate](#checkvaliddate)
@@ -670,6 +671,15 @@ exception. For these cases, there is `check.then`
 
 ----
 
+#### check.found
+
+Great for quickly checking string or array search results
+
+```js
+check.found('foo'.indexOf('f')); // true
+check.found('foo bar'.indexOf('bar')); // true
+```
+
 #### check.regexp
 
 Returns true if the passed value is a regular expression.

check-more-types.js

@@ -78,6 +78,15 @@
     return (Array.isArray(x) || isString(x)) && x.length === k;
   }
 
+  /**
+    Checks if the given index is valid in an array or string or -1
+
+    @method found
+  */
+  function found(index) {
+    return index >= 0;
+  }
+
   function startsWith(prefix, x) {
     return isString(prefix) &&
       isString(x) &&
@@ -741,6 +750,7 @@
     schema: schema,
     raises: raises,
     empty: empty,
+    found: found,
     emptyString: emptyString,
     unempty: unempty,
     unit: unit,

docs/use.md

@@ -564,6 +564,15 @@ exception. For these cases, there is `check.then`
 
 ----
 
+### check.found
+
+Great for quickly checking string or array search results
+
+```js
+check.found('foo'.indexOf('f')); // true
+check.found('foo bar'.indexOf('bar')); // true
+```
+
 ### check.regexp
 
 Returns true if the passed value is a regular expression.

test/unit-tests.js

@@ -202,6 +202,20 @@ describe('check-more-types', function () {
     });
   });
 
+  describe('check/found', function () {
+    it('returns true for found indices', function () {
+      la(check.found('foo'.indexOf('f')));
+      la(check.found('foo'.indexOf('oo')));
+      la(check.found('foo bar'.indexOf('bar')));
+    });
+
+    it('fails for negative numbers', function () {
+      la(!check.found('foo'.indexOf('a')));
+      la(!check.found(-1), '-1');
+      la(!check.found(-2), '-2');
+    });
+  });
+
   describe('check/regexp', function () {
     it('passes regular expressions', function () {
       la(check.regexp(/foo/));