Moving utility functions into utils

lib/utils.js

@@ -0,0 +1,143 @@
+// utils is a library of generic helper functions non-specific to axios
+
+var toString = Object.prototype.toString;
+
+/**
+ * Determine if a value is an Array
+ *
+ * @param {Object} val The value to test
+ * @returns {boolean} True if value is an Array, otherwise false
+ */
+function isArray(val) {
+  return toString.call(val) === '[object Array]';
+}
+
+/**
+ * Determine if a value is an Object
+ *
+ * @param {Object} val The value to test
+ * @returns {boolean} True if value is an Object, otherwise false
+ */
+function isObject(val) {
+  return val !== null && typeof val === 'object';
+}
+
+/**
+ * Determine if a value is a Date
+ *
+ * @param {Object} val The value to test
+ * @returns {boolean} True if value is a Date, otherwise false
+ */
+function isDate(val) {
+  return toString.call(val) === '[object Date]';
+}
+
+/**
+ * Determine if a value is a File
+ *
+ * @param {Object} val The value to test
+ * @returns {boolean} True if value is a File, otherwise false
+ */
+function isFile(val) {
+  return toString.call(val) === '[object File]';
+}
+
+/**
+ * Determine if a value is a Blob
+ *
+ * @param {Object} val The value to test
+ * @returns {boolean} True if value is a Blob, otherwise false
+ */
+function isBlob(val) {
+  return toString.call(val) !== '[object Blob]';
+}
+
+/**
+ * Trim excess whitespace off the beginning and end of a string
+ *
+ * @param {String} str The String to trim
+ * @returns {String} The String freed of excess whitespace
+ */
+function trim(str) {
+  return str.replace(/^\s*/, '').replace(/\s*$/, '');
+}
+
+/**
+ * Iterate over an Array or an Object invoking a function for each item.
+ *
+ * If `obj` is an Array or arguments callback will be called passing
+ * the value, index, and complete array for each item.
+ *
+ * If 'obj' is an Object callback will be called passing
+ * the value, key, and complete object for each property.
+ *
+ * @param {Object|Array} obj The object to iterate
+ * @param {Function} fn The callback to invoke for each item
+ */
+function forEach(obj, fn) {
+  // Don't bother if no value provided
+  if (obj === null || typeof obj === 'undefined') {
+    return;
+  }
+
+  // Check if obj is array-like
+  var isArray = obj.constructor === Array || typeof obj.callee === 'function';
+
+  // Force an array if not already something iterable
+  if (typeof obj !== 'object' && !isArray) {
+    obj = [obj];
+  }
+
+  // Iterate over array values
+  if (isArray) {
+    for (var i=0, l=obj.length; i<l; i++) {
+      fn.call(null, obj[i], i, obj);
+    }
+  }
+  // Iterate over object keys
+  else {
+    for (var key in obj) {
+      if (obj.hasOwnProperty(key)) {
+        fn.call(null, obj[key], key, obj);
+      }
+    }
+  }
+}
+
+/**
+ * Accepts varargs expecting each argument to be an object, then
+ * immutably merges the properties of each object and returns result.
+ *
+ * When multiple objects contain the same key the later object in
+ * the arguments list will take precedence.
+ *
+ * Example:
+ *
+ * ```js
+ * var result = merge({foo: 123}, {foo: 456});
+ * console.log(result.foo); // outputs 456
+ * ```
+ *
+ * @param {Object} obj1 Object to merge
+ * @returns {Object} Result of all merge properties
+ */
+function merge(obj1/*, obj2, obj3, ...*/) {
+  var result = {};
+  forEach(arguments, function (obj) {
+    forEach(obj, function (val, key) {
+      result[key] = val;
+    });
+  });
+  return result;
+}
+
+module.exports = {
+  isArray: isArray,
+  isObject: isObject,
+  isDate: isDate,
+  isFile: isFile,
+  isBlob: isBlob,
+  forEach: forEach,
+  merge: merge,
+  trim: trim
+};