Adding OL.String.isNumeric method to test for numeric strings. r=crschmidt (closes #1441)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@7451 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/BaseTypes.js

@@ -134,6 +134,31 @@ OpenLayers.String = {
             }
         }
         return tokens.join("");
+    },
+    
+    /**
+     * Property: OpenLayers.String.numberRegEx
+     * Used to test strings as numbers.
+     */
+    numberRegEx: /^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/,
+    
+    /**
+     * APIFunction: OpenLayers.String.isNumeric
+     * Determine whether a string contains only a numeric value.
+     *
+     * Examples:
+     * (code)
+     * OpenLayers.String.isNumeric("6.02e23") // true
+     * OpenLayers.String.isNumeric("12 dozen") // false
+     * OpenLayers.String.isNumeric("4") // true
+     * OpenLayers.String.isNumeric(" 4 ") // false
+     * (end)
+     *
+     * Returns:
+     * {Boolean} String contains only a number.
+     */
+    isNumeric: function(value) {
+        return OpenLayers.String.numberRegEx.test(value);
     }
 
 };

tests/BaseTypes.html

@@ -141,6 +141,43 @@
         );
 
     }
+
+    function test_String_isNumeric(t) {
+        var cases = [
+            {value: "3", expect: true},
+            {value: "+3", expect: true},
+            {value: "-3", expect: true},
+            {value: "3.0", expect: true},
+            {value: "+3.0", expect: true},
+            {value: "-3.0", expect: true},
+            {value: "6.02e23", expect: true},
+            {value: "+1.0e-100", expect: true},
+            {value: "-1.0e+100", expect: true},
+            {value: "1E100", expect: true},
+            {value: null, expect: false},
+            {value: true, expect: false},
+            {value: false, expect: false},
+            {value: undefined, expect: false},
+            {value: "", expect: false},
+            {value: "3 ", expect: false},
+            {value: " 3", expect: false},
+            {value: "1e", expect: false},
+            {value: "1+e", expect: false},
+            {value: "1-e", expect: false}
+        ];
+        t.plan(cases.length);
+        
+        var func = OpenLayers.String.isNumeric;
+        var obj, val, got, exp;
+        for(var i=0; i<cases.length; ++i) {
+            obj = cases[i];
+            val = obj.value;
+            exp = obj.expect;
+            got = func(val);
+            t.eq(got, exp, "'" + val + "' returns " + exp);
+        }
+        
+    }
    
    
     function test_Number_limitSigDigs(t) {