add library

Author: logicalparadox

lib/eql.js

@@ -1,2 +1,257 @@
+/*!
+ * deep-eql
+ * Copyright(c) 2013 Jake Luer <jake@alogicalparadox.com>
+ * MIT Licensed
+ */
 
-exports.version = '0.0.0';
+/*!
+ * Module dependencies
+ */
+
+var type = require('type-detect');
+
+/*!
+ * Buffer.isBuffer browser shim
+ */
+
+var Buffer;
+try { Buffer = require('buffer').Buffer; }
+catch(ex) {
+  Buffer = {};
+  Buffer.isBuffer = function() { return false; }
+}
+
+/*!
+ * Primary Export
+ */
+
+module.exports = deepEqual;
+
+/**
+ * Assert super-strict (egal) equality between
+ * two objects of any type.
+ *
+ * @param {Mixed} a
+ * @param {Mixed} b
+ * @param {Array} memoised (optional)
+ * @return {Boolean} equal match
+ */
+
+function deepEqual(a, b, m) {
+  if (sameValue(a, b)) {
+    return true;
+  } else if ('date' === type(a)) {
+    return dateEqual(a, b);
+  } else if ('regexp' === type(a)) {
+    return regexpEqual(a, b);
+  } else if (Buffer.isBuffer(a)) {
+    return bufferEqual(a, b);
+  } else if ('arguments' === type(a)) {
+    return argumentsEqual(a, b, m);
+  } else if (!typeEqual(a, b)) {
+    return false;
+  } else if (('object' !== type(a) && 'object' !== type(b))
+  && ('array' !== type(a) && 'array' !== type(b))) {
+    return sameValue(a, b);
+  } else {
+    return objectEqual(a, b, m);
+  }
+}
+
+/*!
+ * Strict (egal) equality test. Ensures that NaN always
+ * equals NaN and `-0` does not equal `+0`.
+ *
+ * @param {Mixed} a
+ * @param {Mixed} b
+ * @return {Boolean} equal match
+ */
+
+function sameValue(a, b) {
+  if (a === b) return a !== 0 || 1 / a === 1 / b;
+  return a !== a && b !== b;
+}
+
+/*!
+ * Compare the types of two given objects and
+ * return if they are equal. Note that an Array
+ * has a type of `array` (not `object`) and arguments
+ * have a type of `arguments` (not `array`/`object`).
+ *
+ * @param {Mixed} a
+ * @param {Mixed} b
+ * @return {Boolean} result
+ */
+
+function typeEqual(a, b) {
+  return type(a) === type(b);
+}
+
+/*!
+ * Compare two Date objects by asserting that
+ * the time values are equal using `saveValue`.
+ *
+ * @param {Date} a
+ * @param {Date} b
+ * @return {Boolean} result
+ */
+
+function dateEqual(a, b) {
+  if ('date' !== type(b)) return false;
+  return sameValue(a.getTime(), b.getTime());
+}
+
+/*!
+ * Compare two regular expressions by converting them
+ * to string and checking for `sameValue`.
+ *
+ * @param {RegExp} a
+ * @param {RegExp} b
+ * @return {Boolean} result
+ */
+
+function regexpEqual(a, b) {
+  if ('regexp' !== type(b)) return false;
+  return sameValue(a.toString(), b.toString());
+}
+
+/*!
+ * Assert deep equality of two `arguments` objects.
+ * Unfortunately, these must be sliced to arrays
+ * prior to test to ensure no bad behavior.
+ *
+ * @param {Arguments} a
+ * @param {Arguments} b
+ * @param {Array} memoize (optional)
+ * @return {Boolean} result
+ */
+
+function argumentsEqual(a, b, m) {
+  if ('arguments' !== type(b)) return false;
+  a = [].slice.call(a);
+  b = [].slice.call(b);
+  return deepEqual(a, b, m);
+}
+
+/*!
+ * Get enumerable properties of a given object.
+ *
+ * @param {Object} a
+ * @return {Array} property names
+ */
+
+function enumerable(a) {
+  var res = [];
+  for (var key in a) res.push(key);
+  return res;
+}
+
+/*!
+ * Simple equality for flat iterable objects
+ * such as Arrays or Node.js buffers.
+ *
+ * @param {Iterable} a
+ * @param {Iterable} b
+ * @return {Boolean} result
+ */
+
+function iterableEqual(a, b) {
+  if (a.length !==  b.length) return false;
+
+  var i = 0;
+  var match = true;
+
+  for (; i < a.length; i++) {
+    if (a[i] !== b[i]) {
+      match = false;
+      break;
+    }
+  }
+
+  return match;
+}
+
+/*!
+ * Extension to `iterableEqual` specifically
+ * for Node.js Buffers.
+ *
+ * @param {Buffer} a
+ * @param {Mixed} b
+ * @return {Boolean} result
+ */
+
+function bufferEqual(a, b) {
+  if (!Buffer.isBuffer(b)) return false;
+  return iterableEqual(a, b);
+}
+
+/*!
+ * Block for `objectEqual` ensuring non-existing
+ * values don't get in.
+ *
+ * @param {Mixed} object
+ * @return {Boolean} result
+ */
+
+function isValue(a) {
+  return a !== null && a !== undefined;
+}
+
+/*!
+ * Recursively check the equality of two objects.
+ * Once basic sameness has been established it will
+ * defer to `deepEqual` for each enumerable key
+ * in the object.
+ *
+ * @param {Mixed} a
+ * @param {Mixed} b
+ * @return {Boolean} result
+ */
+
+function objectEqual(a, b, m) {
+  if (!isValue(a) || !isValue(b)) {
+    return false;
+  }
+
+  if (a.prototype !== b.prototype) {
+    return false;
+  }
+
+  var i;
+  if (m) {
+    for (i = 0; i < m.length; i++) {
+      if ((memos[i][0] === a && memos[i][1] === b)
+      ||  (memos[i][0] === b && memos[i][1] === a)) {
+        return true;
+      }
+    }
+  } else {
+    m = [];
+  }
+
+  try {
+    var ka = enumerable(a);
+    var kb = enumerable(b);
+  } catch (ex) {
+    return false;
+  }
+
+  ka.sort();
+  kb.sort();
+
+  if (!iterableEqual(ka, kb)) {
+    return false;
+  }
+
+  m.push([ a, b ]);
+
+  var key;
+  for (i = ka.length - 1; i >= 1; i--) {
+    key = ka[i];
+    if (!deepEqual(a[key], b[key], m)) {
+      return false;
+    }
+  }
+
+  return true;
+}