basic overloadable functions

2 files changed, 69 insertions, 0 deletions

diff --git a/README.md b/README.md
index e743971..c72c0ce 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,17 @@
 # jfn
 Playing around with Javascript functions
+
+A global overloadable function:
+
+```
+jfn.defineFunction("testFunction", ["string"], function (str) {
+    alert("String: " + str);
+});
+
+jfn.defineFunction("testFunction", ["number"], function (num) {
+    alert("Num: " + num);
+});
+
+testFunction("Hello!"); //String: Hello!
+testFunction(1); //Num: 1
+```
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diff --git a/jfn.js b/jfn.js
new file mode 100644
index 0000000..90b725e
--- /dev/null
+++ b/jfn.js
@@ -0,0 +1,54 @@
+var jfn = {};
+
+jfn.getProxyFunction = function (name) {
+    return function () {
+        var jfns = this[name]["__jfns"];
+        
+        for (var i = 0; i < jfns.length; i++) {
+            var jfn = jfns[i];
+            
+            var matches = arguments.length === jfn.args.length;
+            for (var a = 0; a < jfn.args.length; a++) {
+                matches = jfn.args[a] === (typeof arguments[a]);
+                if (!matches) {
+                    break;
+                }
+            }
+            
+            if (matches) {
+                jfn.fn.apply(this, arguments);
+                return;
+            }
+        }
+    };
+};
+
+jfn.defineFunction = function (object, name, args, fn) {
+    if (typeof object === "string") {
+        fn = args;
+        args = name;
+        name = object;
+        object = window;
+    }
+    
+    if (!object.hasOwnProperty(name)) {
+        object[name] = jfn.getProxyFunction(name);
+    }
+    
+    if (!object[name].hasOwnProperty("__jfns")) {
+        object[name]["__jfns"] = [];
+    } else {
+        for (var i = 0; i < object[name]["__jfns"].length; i++) {
+            var f = object[name]["__jfns"][i];
+            if (JSON.stringify(f.args) === JSON.stringify(args)) {
+                object[name]["__jfns"].splice(i, 1);
+                return;
+            }
+        }
+    }
+    
+    object[name]["__jfns"].push({
+        args: args,
+        fn: fn
+    });
+};
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