RAHHH

backend/frontend/node_modules/tcomb/lib/maybe.js

@@ -0,0 +1,57 @@
+var assert = require('./assert');
+var isTypeName = require('./isTypeName');
+var isFunction = require('./isFunction');
+var isMaybe = require('./isMaybe');
+var isIdentity = require('./isIdentity');
+var Any = require('./Any');
+var create = require('./create');
+var Nil = require('./Nil');
+var forbidNewOperator = require('./forbidNewOperator');
+var is = require('./is');
+var getTypeName = require('./getTypeName');
+
+function getDefaultName(type) {
+  return '?' + getTypeName(type);
+}
+
+function maybe(type, name) {
+
+  if (isMaybe(type) || type === Any || type === Nil) { // makes the combinator idempotent and handle Any, Nil
+    return type;
+  }
+
+  if (process.env.NODE_ENV !== 'production') {
+    assert(isFunction(type), function () { return 'Invalid argument type ' + assert.stringify(type) + ' supplied to maybe(type, [name]) combinator (expected a type)'; });
+    assert(isTypeName(name), function () { return 'Invalid argument name ' + assert.stringify(name) + ' supplied to maybe(type, [name]) combinator (expected a string)'; });
+  }
+
+  var displayName = name || getDefaultName(type);
+  var identity = isIdentity(type);
+
+  function Maybe(value, path) {
+    if (process.env.NODE_ENV !== 'production') {
+      if (identity) {
+        forbidNewOperator(this, Maybe);
+      }
+    }
+    return Nil.is(value) ? value : create(type, value, path);
+  }
+
+  Maybe.meta = {
+    kind: 'maybe',
+    type: type,
+    name: name,
+    identity: identity
+  };
+
+  Maybe.displayName = displayName;
+
+  Maybe.is = function (x) {
+    return Nil.is(x) || is(x, type);
+  };
+
+  return Maybe;
+}
+
+maybe.getDefaultName = getDefaultName;
+module.exports = maybe;